Handbook Of Medications

Handbook of Medications for the NCLEX-RN® Review MARGARET M. DAHLHAUSER, RN, PhD Professor Emeritus School of Nursing Tennessee State University Nashville, Tennessee

McGRAW-HILL, INC. Medical Publishing Division New York Chicago San Francisco Lisbon Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto

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Contents

CHAPTER 1

INTRODUCTION TO MEDICATIONS

CHAPTER 2

PERIPHERAL NERVOUS SYSTEM AGENTS

CHAPTER 3

CENTRAL NERVOUS SYSTEM AGENTS

CHAPTER 4

DRUGS THAT AFFECT FLUID AND ELECTROLYTE BALANCE

CHAPTER 5

CARDIOVASCULAR DRUGS

CHAPTER 6

DRUGS THAT AFFECT THE BLOOD

CHAPTER 7

ENDOCRINE DRUGS

CHAPTER 8

DRUGS FOR INFLAMMATORY AND ALLERGIC DISORDERS

CHAPTER 9

RESPIRATORY TRACT DRUGS

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20 35

42 56

70

CHAPTER 10 GASTROINTESTINAL DRUGS ii

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98 105

88

Contents ◆ iii CHAPTER 11 OPHTHALMIC DRUGS

115

CHAPTER 12 CHEMOTHERAPY USED TO TREAT INFECTIOUS DISEASES CHAPTER 13 ANTICANCER DRUGS

144

CHAPTER 14 IMMUNOSUPPRESSIVE DRUGS

150

CHAPTER 15 DRUG THERAPY FOR OSTEOPOROSIS CHAPTER 16 DRUGS USED TO TREAT POISONING

152 156

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Chapter

1

Introduction to Medications

Few areas relevant to nursing practice have expanded as rapidly as the area of drug therapy. Many new drugs are marketed yearly, and there are frequent changes in how to use both recently developed and classic drugs as a result of research and experience. The same drug may be used to treat different conditions and diseases. Most drugs have several names; the most common are the generic name and the trade name. The generic name is related to the chemical name and is independent of the manufacturer. The trade name is designated and patented by the manufacturer. In this handbook, the most commonly used name, whether trade or generic, will appear in boldface type. If both names are equally recognizable both will appear in boldface type. Administering medications to clients is a nurse’s important, and frequently primary, responsibility. The administration of medications is guided by the five rights: the right drug, the right dose, the right client, by the right route, at the right time. To accomplish this goal, the nurse must be able to interpret drug orders accurately, select correct drug preparation, calculate drug dosage accurately, and use different routes of administration safely and accurately. The nurse must also be able to document accurately and know about drug interactions and side effects as well as be able to teach the patient how to use drugs accurately.

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◆ Chapter 1

DISPENSING MEDICATIONS Each agency has a system for dispensing drugs. A commonly used method is the unitdose system, in which most drugs are dispensed in single-dose or unit-dose packages containing, for example, one tablet or one capsule. Medication orders written by the physician are first checked by the medical secretary, and a registered nurse (RN), and the order is sent to the pharmacy. Pharmacy personnel place the medications in a container that is delivered to the nursing personnel, who distribute them to the client. Most hospitals use computerized mechanisms and a device to scan the patient’s arm band and the barcodes on medications to ensure accuracy.

CALCULATING DRUG DOSAGE A few drugs are ordered and measured in terms of units (U) or milliequivalents (mEq). Units are unique for each drug. Concentrations of insulin, heparin, and penicillin are expressed in units; however, there is no relationship between a unit of insulin and a unit of heparin. These medications are usually ordered in the number of units per dose. For example, an order for NPH insulin 20 U SC every morning at 7 a.m. or heparin 2000 U SC every 12 h will be labeled in the number of units per milliliter (U 100 insulin contains 100 U/mL); heparin may have 1000, 5000, or 10,000 U/mL. Drugs such as potassium chloride are ordered in the number of milliequivalents per dose and labeled in terms of milliequivalents per dosage (e.g., they may have 10, 20, or 30 mEq/mL). Most physician’s medication orders are expressed in metric units of measure. If the amount of medication ordered is the same as that on the drug label, no calculations are required, and preparing the correct dose is a simple matter. For example, if the physician orders codeine 20 mg PO, and the drug label reads “codeine 20 mg tablets,” it is clear that one tablet is to be administered to the client. What happens if the order calls for codeine 20 mg and only codeine 10 mg is available? Calculations are then necessary to determine how many codeine tablets are needed to give a dose of 20 mg. This can be done by simple mathematics: O 20 mg (O) = = 2 tablets codeine H 10 mg (H) When the order and label of the drug on hand are in different systems, the nurse’s first step is to change what is ordered into what is on hand, and then divide what is available into what is ordered. Simple mathematical methods for doing this are presented in Appendix A of NCLEX Review. The most commonly used system of measurement is the metric system, which uses grams for weight and liters for volume. The apothecary system uses grains, minims, drams, ounces, pounds, pints, and quarts; the household system uses teaspoons, tablespoons, and drops. All three systems are used in the administration of drugs.

Introduction to Medications ◆ 3

COMMON ABBREVIATIONS The current trend is to discourage use of abbreviations because of their statistical correlation to dosing errors. Most hospitals have a list of acceptable abbreviations, but their use is strictly limited.

MEDICATION, PREPARATION, METHOD OF ADMINISTRATION, AND INTERACTIONS Forms of systemic drugs include liquids, capsules, and tablets, as well as transdermal, IV, IM, and pump delivery. Some drugs are available in only one preparation or dosage form; others are available in several forms. Route of administration affects drug actions and response times by influencing absorption and distribution. The IV route is the most rapid and effective route because the drug is injected into the bloodstream, thus bypassing barriers to absorption. Many drugs can be administered by the IM route; these produce action within a few minutes because muscles have an abundant blood supply. The oral route (PO) generally produces slower drug action than parenteral routes. Absorption and action of topical drugs vary according to the specific method of administration. Transdermal forms of medications are absorbed through the skin and include systemically absorbed nitroglycerin and scopolamine. Some other methods of drug delivery are listed below.

r Pump delivery systems may be external (outside the skin) or implanted (under the skin) and are refillable.

r An implanted vascular access device may be used to deliver chemotherapy directly to a cancerous organ. Medication is administered using a special needle (Huber) that fits into the implanted catheter.

r An external pump using a Hickman catheter may be used for systemic delivery (e.g., total parenteral nutrition [TPN]).

r In continuous venovenous hemodialysis, blood is pumped from a double lumen venous catheter through a hemofilter and returned to the patient through the same catheter. There is no arterial access required and the system can be set up, used, maintained, and terminated by critical care nurses. This system is increasingly being used to manage acute renal failure.

r An implanted needle may also be used to deliver insulin at a set dosage and a set time schedule, thus eliminating the need for SC insulin injections. The external pump is attached to the patient’s clothing and is used to deliver insulin through a catheter via a needle inserted subcutaneously, usually in the abdominal area. Narcotic analgesics may be delivered by an external pump called a patient-controlled analgesic pump (PCAP); a peripheral line or a central IV line (e.g., Hickman catheter) is used with

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◆ Chapter 1 the PCAP. The advantages of a PCAP are that it provides prolonged parenteral administration, there is no delay in drug administration, it avoids repetitive injections, it delivers consistent drug levels, and it usually decreases the amount of analgesic used. Enteric-coated tablets and capsules are coated with a substance that is insoluble in gastric juices, so these medications do not dissolve until they reach the intestine, thus avoiding gastric irritation and keeping the drug from being destroyed by gastric juices. Several controlled-release dosage forms (sustained-release tablets and capsules) have been developed to allow less frequent administration and more consistent serum drug levels. These tablets or capsules should not be crushed for administration. If the client cannot swallow them, contact the physician for advice on another route of administration.

Some foods contain substances that react with certain drugs, for example, the interaction between tyramine-containing foods and monoamine oxidase inhibitors (MAOIs). Tyramine causes the release of norepinephrine (a potent vasoconstrictive agent) from the adrenal medulla and sympathetic neurons. The MAOI slows the breakdown of norepinephrine. As a result of these two actions, the client may experience severe hypertension. Another common example is the potential interaction that may occur between oral anticoagulants such as warfarin (Coumadin) and foods containing vitamin K. Because vitamin K antagonizes the action of oral anticoagulants, large amounts of green leafy vegetables such as spinach may offset the effects of anticoagulants and predispose the client to thromboembolic disease. Vitamin K is necessary for the production of prothrombin, an important clotting factor. Body weight affects drug action mainly in terms of dosage. The ratio between the amount of drug given and the body weight influences drug distribution. The recommended dosage for many drugs is given in terms of grams or milligrams per kilogram of body weight. Most pediatric drug dosages are calculated with formulas that use body weight to determine the correct dosage. Attitudes and expectations related to a particular drug may influence the client’s response, as can psychological conditions. In the placebo effect, for example, substances such as sodium chloride solution are sometimes given to clients addicted to analgesic narcotics to satisfy a demand for the addicting drug. The client does not know he or she has received placebo, and if the client believes the placebo is the real drug, he or she will usually respond as if given the actual medication. The action of a particular drug may be increased or decreased by its interaction with another drug in the body. Drugs may have an additive effect (e.g., alcohol taken with sedative drugs increases sedation). Pathologic (disease) conditions often alter the effects of drugs. Severe liver failure will cause certain drugs to remain in the body for long periods because the failing liver cannot break down the drug and excrete it. Narcotic analgesics must be given in very small doses to a client with severe liver failure; otherwise the client may suffer from overdose. Severe or chronic diarrhea will cause rapid loss of oral medications. Excretion of medications decreases with severe kidney disease. Hyperthyroidism and fever cause increased metabolism of drugs.

Introduction to Medications ◆ 5 Antagonism occurs when a drug decreases the effects of a group of drugs (e.g., naloxone [Narcan], a narcotic antagonist). This drug may be given to relieve narcoticinduced respiratory depression caused by morphine, a narcotic analgesic.

VARIABLES INFLUENCING DOSAGE AND ACTIONS OF DRUGS There are many variables that may influence the dosage and actions of drugs. The first step in individualizing drug therapy is to assess such variables as the client’s age, disease, and current medications. While drug therapy should be integrated with other aspects of health care, appropriate non-drug measures should be used to decrease the need for drugs, to enhance the therapeutic effects of drugs, or to decrease any adverse effects. One final note: Nursing implications are not listed for every drug in this book, but adverse side effects and client educational needs should be viewed as implications for nursing.

Chapter

2

Peripheral Nervous System Agents

MUSCARINIC AGONISTS AND ANTAGONISTS r The muscarinic agonists are drugs that bind to muscarinic receptors and thereby cause their activation.

r Since nearly all muscarinic receptors are associated with the parasympathetic nervous system, the responses to muscarinic agonists closely resemble those produced by stimulation of parasympathetic nerves.

r Because their effects resemble those of parasympathetic stimulation, muscarinic agonists are known alternatively as parasympathomimetic agents or cholinergic agents.

r The muscarinic agonists, represented by bethanechol (Urecholine), are drugs that selectively mimic the effects of acetylcholine at muscarinic receptors.

ANTICHOLINERGIC AGENTS r The muscarinic antagonists are drugs that competitively block the action of acetylcholine at muscarinic receptors. 6

Peripheral Nervous System Agents ◆ 7

r The muscarinic antagonists are also known as parasympatholytic, muscarinic cholinergic blocking agents or anticholinergic drugs.

◆ Cholinergic Agents (Parasympathetic Nervous System) Generic Name

Trade Name

Bethanechol Desired effect: Major side effects:

Myotonachol Myotonachol is given to contract the urinary bladder, causing bladder emptying. Cardiac arrest, abdominal discomfort, diarrhea, nausea, vomiting, salivation, urinary urgency, and sweating Myotonachol is used in the treatment of acute postpartum and postoperative nonobstructive urinary retention and in retention due to neurogenic bladder. Administer myotonachol on an empty stomach to avoid nausea and vomiting; monitor response to establish minimum effective dose; report diarrhea, headache, and dizziness. Tensilon (also used to diagnose myasthenia gravis) Prostigmin Mestinon Tensilon, Prostigmin, and Mestinon inhibit the breakdown of acetylcholine, so it accumulates and has a prolonged effect. These agents may cause seizures, excessive secretions, bronchospasm, bradycardia, and abdominal cramps. They are used to increase muscle strength in symptomatic treatment of myasthenia gravis, and for prevention and treatment of postoperative bladder distention and urinary retention or ileus. Pilocar It directly stimulates cholinergic receptors, resulting in decreased intraocular pressure and miosis (abnormal contraction of the pupils). Blurred vision, eye pain, and increased sweating It is used alone or with other agents in the treatment of glaucoma. The nurse needs to report severe side effects of profound dizziness, and instruct the patient to arise from a lying position slowly to avoid dizziness due to orthostatic hypotension.

Treatment: Nursing implications:

Edrophonium Neostigmine Pyridostigmine Desired effects: Major side effects: Treatment:

Pilocarpine Desired effect: Major side effects: Treatment: Nursing implications:

r Atropine is the best known muscarinic antagonist. It is found naturally in a variety of plants, including Atropa belladonna.

r Because of the presence of belladonna in, for example, Donnatal, it is referred to as a belladonna alkaloid.

r It is easier to understand responses to anticholinergic agents if you first know about the response to cholinergic agents. Cholinergic agents cause bradycardia, sweating, salivation, increased bronchial and gastric acid secretions, and an increase in gastrointestinal peristalsis.

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◆ Chapter 2

◆ Anticholinergic Agents Generic Name

Trade Name

Atropine Desired effect:

No trade name Increased heart rate (drug of choice for bradycardia); decreased GI and respiratory secretions Drowsiness, blurred vision, tachycardia, and dry mouth IM: Preoperative medication to inhibit salivation and excessive respiratory secretions; treatment of bradycardia and syncope due to hyperactive carotid sinus reflex, treatment of parkinsonism; relieves tremor and rigidity PO: Adjunctive therapy in the management of peptic ulcer and irritable bowel syndrome

Major side effects: Treatment:

Note: Atropine is contraindicated in clients with glaucoma, chronic obstructive pulmonary disease (COPD), cardiac arrhythmias, myocardial ischemia, and impaired liver function.

Belladonna tincture Treatment: Desired effect: Major side effects: Benztropine Treatment: Desired effect: Major side effects: Glycopyrrolate Desired effect: Major side effects: Treatment: Propantheline Desired effect: Major side effects: Treatment: Scopolamine Treatment:

Donnatal Used to treat spastic colon (drug of choice for diverticulosis) Provides peripheral anticholinergic/antispasmodic action and mild sedation Urinary hesitancy and retention, blurred vision, tachycardia, and palpitation Cogentin Adjunctive treatment of all forms of Parkinson’s disease, including drug-induced extrapyramidal effects (e.g., Haldol) Blocks cholinergic activity in the CNS, which is partially responsible for the symptoms of Parkinson’s disease; reduction of rigidity and tremors Dry eyes, blurred vision, constipation, dry mouth, tachycardia Robinul Inhibits the action of acetylcholine at postganglionic sites Blurred vision, tachycardia, dry mouth, constipation, and urinary hesitancy Used as a preoperative medication to inhibit salivation and excessive respiratory secretions Pro-Banthine Competitively inhibits the muscarinic action of acetylcholine, resulting in decreased GI secretions Drowsiness, blurred vision, tachycardia, dry mouth, constipation, and urinary retention Adjunctive therapy in the treatment of peptic ulcer disease • Hyoscine Reduction of nausea and vomiting associated with motion sickness and depressing salivary and bronchial secretion; this occurs by blocking the effects of acetylcholine at muscarinic cholinergic receptors that mediate the effects of parasympathetic impulses, thus inhibiting vagal influences on the heart, relaxing the GI and GU tracts, inhibiting gastric secretions, relaxing the pupil of the eye (mydriatic effect), and preventing accommodation for near vision (cycloplegic effect).

Peripheral Nervous System Agents ◆ 9

◆ Anticholinergic Agents (continued) Generic Name

Trade Name

Major side effects:

Pupil dilation, photophobia, blurred vision, headache, drowsiness, dizziness, dry mouth, urinary hesitancy, and nasal congestion Prevention of motion sickness (transdermal); preoperatively to produce amnesia and decrease salivation and excessive respiratory secretions Educate the patient to take the drug as prescribed 30–60 minutes before meals and avoid excessive dosage; avoid alcohol because serious sedation could occur; the patient may experience heat intolerance and dangerous reactions may occur. Apo-Trihex (Canada) Diminished signs and symptoms of parkinsonian syndrome (tremors and rigidity) Dizziness, nervousness, blurred vision, dry mouth, constipation, and urinary retention Adjunct in the management of parkinsonian syndrome due to many causes, including drug-induced parkinsonism

Treatment:

Nursing implications:

Trihexyphenidyl Desired effect: Side effects: Treatment:

CHOLINESTERASE INHIBITORS r Cholinesterase inhibitors are drugs that prevent the degradation of acetylcholine by cholinesterase.

r Neostigmine typifies the reversible cholinesterase inhibitors and serves as a prototype for the group.

◆ Cholinesterase Inhibitors Generic Name

Trade Name

Pyridostigmine bromide Desired effect:

Mestinon Improved muscular function in clients with myasthenia gravis and improved bladder emptying in clients with urinary retention Excessive secretions, bronchospasm, bradycardia, abdominal cramps, diarrhea, excessive salivation, and sweating Used to increase muscle strength in symptomatic treatment of myasthenia gravis; prevention and treatment of postoperative bladder distention and urinary retention or ileus

Major side effects: Treatment:

(continued)

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◆ Chapter 2

◆ Cholinesterase Inhibitors (continued) Generic Name

Trade Name

Neostigmine Desired effect:

Prostigmin Increases the concentration of acetylcholine at the sites of cholinergic transmission, and prolongs and exaggerates the effect of acetylcholine by reversible inhibiting of the enzyme acetylcholinesterase, causing parasympathomimetic effects and facilitating transmission at the skeletal neuromuscular junction; also has direct cholinomimetic activity on neurons in the autonomic ganglia and the CNS Seizures, dysarthria, drowsiness, cardiac arrhythmias, thrombophlebitis, laryngospasm, bronchospasm, urinary frequency, and incontinence Prevention and treatment of postoperative distention and urinary retention; symptomatic control of myasthenia gravis; diagnosis of myasthenia gravis; antidote for nondepolarizing junction blockers (e.g., tubocurarine) after surgery Educate the patient to take the drug exactly as prescribed; significant others should receive extensive education about the effects of the drug, the signs and symptoms of myasthenia gravis, the fact that muscle weakness may be related to both drug overdose and to exacerbation of the disease, and that it is important to report muscle weakness promptly to the nurse or physician so that proper evaluation can be made.

Major side effects: Treatment:

Nursing implications:

ADRENERGIC AGENTS (SYMPATHETIC NERVOUS SYSTEM) r Adrenergic agonists are drugs that produce their effects by causing activation of adrenergic receptors.

r Since the sympathetic nervous system acts through those same receptors, responses to adrenergic agonists and to stimulation by the sympathetic nervous system are very similar.

r Adrenergic agonists have a broad spectrum of clinical applications, ranging from treatment of heart failure to relief of asthma to delay of preterm labor.

r Adrenergic agonists fall into three major chemical classes: naturally occurring catecholamines, synthetic catecholamines, and noncatecholamines. There are several different types of adrenergic receptors. 1. Alpha-1 receptors are located in peripheral blood vessels, sex organs, and radial muscle of the iris in the eye. a. Activation of alpha-1 receptors in the eye produces mydriasis (dilation of the pupil). b. Activation of alpha-1 receptors in blood vessels produces vasoconstriction. c. Activation of alpha-1 receptors in the penis causes ejaculation.

Peripheral Nervous System Agents ◆ 11 2. Alpha-2 receptors are located in the peripheral blood vessels; however, the ability to activate alpha-2 receptors has only minimal clinical significance. 3. Beta-1 receptors are located in the heart and the kidney. Cardiac beta-1 receptors have great therapeutic significance. a. Activation of beta-1 receptors increases heart rate; force of contraction (inotropic effect) and speed impulse conduction is controlled through the atrioventricular (A-V) node. b. Activation of beta-1 receptors in the kidney causes release of renin into the blood, causing peripheral vasoconstriction. 4. Beta-2 receptors are located in the lungs, uterus, and liver. a. Activation of beta-2 receptors in the uterus causes relaxation of uterine smooth muscle.

◆ Naturally Occurring Catecholamines Drug

Receptors

Dopamine Norepinephrine Epinephrine

Dopaminergic, beta-1, and alpha-1 Alpha-1, alpha-2, and beta-1 Beta-1, beta-2, alpha-1, and alpha-2

b. Activation of beta-2 in arterioles of the lungs causes bronchiolar vasodilation. c. Activation of beta-2 receptors in the liver promotes glycogenolysis (breakdown of glycogen into glucose), thereby increasing blood levels of glucose. The noteworthy adverse response to beta-2 activation is hyperglycemia (elevation of blood glucose). d. Beta-2 receptors are not present in the heart. 5. Dopamine is the only drug available that can activate dopamine receptors. a. The degree of receptor specificity displayed by dopamine is dose dependent. When administered in low therapeutic doses, dopamine acts on dopamine receptors only. b. At low doses (1–2 g/kg per minute) dopamine dilates renal mesenteric blood vessels, producing an increase in urinary output. c. At moderate to large doses (2–10 g/kg per minute) dopamine activates beta-2 receptors in addition to dopamine receptors, increasing cardiac output. d. In very high doses (10 g/kg per minute), dopamine activates alpha-1, beta-1, and dopamine receptors, causing vasoconstriction; therefore, it is used in high doses to treat hypotension (shock) because in such doses it will increase blood pressure. Catecholamines (dopamine, norepinephrine, and epinephrine) are synthesized, stored, and metabolized in the brain.

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◆ Chapter 2

SYNTHETIC CATECHOLAMINES 1. Synthetic catecholamines include albuterol (Proventil and Ventolin), isoetharine (Bronkosol), metaproterenol (Alupent), and terbutaline (Brethine). a. All of these drugs selectively activate beta-2 receptors in the lungs and are used as bronchodilators. b. Isoproterenol (Isuprel, also a synthetic catecholamine) activates beta-1 and beta-2 receptors. The desired effect is bronchodilation and management of ventricular arrhythmias due to A-V block. c. Dobutamine (Dobutrex) is also a synthetic catecholamine. Dobutrex activates beta-1 receptors, increasing coronary blood flow and heart rate by acting on beta-1 receptors in the heart. The primary indication for the drug is heart failure.

◆ Beta-Adrenergic Agents (Drugs that Act Like Epinephrine) Generic Name

Trade Name

Albuterol (synthetic catecholamine, beta activity) Desired effect:

Proventil, Ventolin

Major side effects: Treatment: Dobutamine (synthetic catecholamine, beta activity) Desired effects: Major side effects: Treatment: Dopamine (catecholamine; dopamine and beta-1 activity) Desired effect and nursing implication:

Bronchodilation and increased blood flow to the heart; causes peripheral vascular constriction because beta-2 receptors are activated Nervousness, restlessness, tachycardia, dry mouth, and hyperglycemia Used as a bronchodilator in reversible airway obstruction due to asthma or chronic obstructive pulmonary disease (COPD) Dobutrex

Increases force of myocardial contractions (inotropic effect), thereby increasing cardiac output without significantly increasing heart rate Tachycardia, hypertension, and premature ventricular contractions Short-term management of heart failure due to depressed contractility from organic heart disease or surgical procedures No commonly used trade name

Dopamine use is dose-dependent: 1. Increases blood pressure when given in large doses. 2. In moderate doses, dopamine increases myocardial contractility (inotropic effect) and cardiac rate, resulting in increased cardiac output. 3. It improves renal blood flow when administered in low doses.

Peripheral Nervous System Agents ◆ 13

◆ Beta-Adrenergic Agents (Drugs that Act Like Epinephrine) (continued) Generic Name

Trade Name

Major side effects: Treatment:

Hypertension, tachycardia, and headache Hypotension; decreased cardiac output; shock unresponsive to fluid replacement Bronkosol Bronchodilation Nervousness, restlessness, tremor, headache, tachycardia, and dry mouth Used as a bronchodilator in reversible airway obstruction due to asthma or COPD Isuprel

Isoetharine Desired effect: Major side effects: Treatment: Isoproterenol (synthetic catecholamine, beta activity and vasoconstriction [parenteral]) Desired effect: Major side effects: Treatment:

Bronchodilation; increased heart rate; increased cardiac output Nervousness, restlessness, tremor, headache, arrhythmias, and hypertension Used as a bronchodilator in reversible airway obstruction due to COPD (inhaled); management of ventricular arrhythmias due to A-V blocks (parenteral); treatment of shock associated with decreased cardiac output and vasoconstriction (parenteral)

Note: This drug is not used very much any more because of severe side effects.

Metaproterenol (synthetic catecholamine, beta activity) Desired effect: Major side effects: Treatment: Terbutaline (synthetic catecholamine, beta activity) Desired effect: Major side effects: Treatment:

Alupent

Bronchodilation Nervousness, restlessness, tremors, hypertension, and hyperglycemia Used as a bronchodilator in reversible airway obstruction due to COPD Brethine

Bronchodilation Nervousness, restlessness, tremors, hypertension, and pulmonary edema Used as a bronchodilator in reversible airway obstruction due to COPD

Note: The beta-adrenergic agonists are used for bronchodilation or to increase cardiac output and they have common side effects.

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◆ Chapter 2

◆ Alpha- and Beta-Adrenergic Agents Generic Name

Trade Name

Ephedrine (synthetic catecholamine, alpha and beta activity) Desired effects:

No trade name

Major side effects:

Treatment:

Nursing implications:

Epinephrine (adrenaline) (naturally occurring catecholamine with beta-1, beta-2, and alpha-1 activity) Desired effect:

Side effects: Treatment:

Nursing implications:

Effects mediated by these receptors include vasoconstriction (increased BP and decreased nasal congestion via alpha receptors), cardiac stimulation (via beta-1 receptors), and bronchodilation (via beta-2 receptors) Fear, anxiety, tenseness, dizziness, nervousness, vertigo, rebound congestion (with nasal use), arrhythmias, decreased urine formation dysuria, and rapid development of tolerance Used as a bronchodilator in management of reversible airway obstruction; relief of nasal congestion in viral upper respiratory tract infections or allergic rhinitis Protect solution from light; give only if clear; discard any unused portion; monitor urine output with parenteral administration; initially urine formation may be constricted and urine formation decreased; do not use as a nasal decongestant for longer than 2–5 days. Bronkaid

Bronchodilation; increases rate and force of cardiac contractions and peripheral vasoconstriction; decreased formation of aqueous humor and increased aqueous outflow Nervousness, restlessness, insomnia, tremor, headache, arrhythmias, and hyperglycemia Use IV in ventricular arrest after other measures have failed to restore circulation; should be given only by trained personnel via intracardiac puncture and intramyocardial injection; treatment and prophylaxis for cardiac arrest and attacks of transitory A-V heart block with syncopal seizures; injection used for relief of respiratory distress due to bronchial asthma, chronic bronchitis, and emphysema; used as a bronchodilator in the symptomatic treatment of asthma and hypotension because it can activate alpha-1 receptors, causing vasoconstriction; use in cardiac arrest (IV and intracardiac) as an adjunct in the localization of anesthesia Use with extreme caution when calculating and preparing; epinephrine is a very potent drug; small errors in dosage can cause serious adverse effects; double-check pediatric dosage; protect drug solution from light, extreme heat, and freezing; do not use pink or brown solution; shake the suspension for injection well before withdrawing the dose; rotate subcutaneous injections to prevent necrosis.

Peripheral Nervous System Agents ◆ 15

◆ Alpha- and Beta-Adrenergic Agents (continued) Generic Name

Trade Name

Norepinephrine (naturally occurring catecholamine, alpha-1, alpha-2, and beta-1 activity) Desired effect: Major side effects:

Levophed

Treatment:

Phenylephrine (synthetic catecholamine, parenteral, alpha activity, vasopressor, decongestant) Desired effect:

Major side effects:

Treatment:

Metaraminol (synthetic catecholamine, alpha and beta activity) Desired effects: Side effects: Treatment:

Increased blood pressure; increased cardiac output Dizziness, somnolence, headache, hallucinations, cardiac arrest, cardiac arrhythmias, impotence, diarrhea, hepatitis, and pancreatitis Restoration of BP to control certain acute hypotensive states (pheochromocytomectomies, septicemia, drug reaction, and adjunct in the treatment of cardiac arrest and profound hypotension Neo-Synephrine

Powerful postsynaptic alpha-adrenergic agent; receptor stimulant that causes vasoconstriction and increased systolic and diastolic BP with little effect on the beta receptors of the heart Weakness, dizziness, restlessness, anxiety, dries nasal mucosa, arrhythmias, acute prolonged hypotensive episodes, tachycardia, and bradycardia Treatment of vascular failure in shock, and as an adjunct for the treatment of shock to correct hypotension that may persist after adequate fluid replacement; when administered parenterally it is used to prolong spinal anesthesia (can also be administered SC, IM, and IV). Aramine

Maintenance of blood pressure and perfusion of vital organs Apprehension, anxiety, restlessness, dizziness, and arrhythmias Management of hypotension and circulatory shock unresponsive to fluid volume replacement, which may occur as a consequence of hemorrhage, drug reaction, or anesthesia

ADRENERGIC ANTAGONISTS (ALPHA AND BETA BLOCKERS) r Adrenergic antagonists cause direct blockade of adrenergic receptors. r Adrenergic antagonists display a high degree of receptor specificity. Because of this specificity, the adrenergic blocking agents can be neatly divided into two major

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◆ Chapter 2 groups: alpha-adrenergic blocking agents (drugs that produce selective blockade of alpha-adrenergic receptors), and beta-adrenergic agents (drugs that produce selective blockade of beta receptors).

r Remember it is much easier to understand responses to alpha or beta blockers if you first know the response to activation of adrenergic receptors.

r If you have not yet mastered (memorized) alpha and beta responses, you should do so now (or at least keep this information close at hand as you proceed).

◆ Beta-Adrenergic Blockers Generic Name

Trade Name

Acebutolol Atenolol Betaxolol

Sectral (beta-1) Tenormin (beta-1) Betoptic (beta-1)

Carteolol HCl Metoprolol Penbutolol Bisoprolol fumarate Nadolol Pindolol Propranolol Sotalol HCl Timolol Terazosin Desired effects:

Cartrol (beta-1 and beta-2) Lopressor, Toprol-XL (beta-1) Levatol (beta-1) Zebeta (beta-1) Corgard (beta-1 and beta-2) Visken (beta-1 and beta-2) Inderal, Inderal LA (beta-1 and beta-2) Betapace (beta-1 and beta-2) Timoptic, Blocadren (beta-1 and beta-2) Hytrin (alpha-1) Beta-adrenergic blockers are antianginal, antiarrhythmic, and antihypertensive; they decrease the influence of the sympathetic nervous system on these tissues, the excitability of the heart, cardiac workload, oxygen consumption, and the release of renin, and thus they lower blood pressure. Bradycardia, tachycardia, fatigue due to CHF, bronchospasm, and hypotension; impotence and decreased libido Hypertension, cardiac dysrhythmias, angina pectoris, and myocardial infarction Slows A-V conduction, decreases cardiac rate and oxygen consumption, and causes vasodilation Do not stop these drugs abruptly after long-term therapy; taper drug gradually over 2 weeks with monitoring; give drug orally with food to facilitate absorption; beta-blockers cannot be discontinued abruptly, and to do so can cause life-threatening arrhythmias and hypertension. For beta-1 blockers: Take apical pulse rate before administration. For beta-2 blockers: Take blood pressure before administration.

Major side effects: Treatment: Desired effects: Nursing implications:

Note:

Peripheral Nervous System Agents ◆ 17

◆ Beta-Adrenergic Blockers (continued) Generic Name

Trade Name

Contraindications

1. Beta-1 blockers—bradycardia 2. Beta-2 blockers—bronchospasm (COPD) and hypotension 3. Alpha-1 blockers—hypotension Timolol and betaxolol are also used to treat glaucoma; Hytrin is also used to relieve symptoms of an enlarged prostate gland.

Other:

Note: The heart has beta-1 receptors and alpha-1 receptors; the lungs have beta-2 receptors; peripheral blood vessels have alpha-1 and beta-2 receptors.

◆ Beta- and Alpha-Adrenergic Blockers Generic Name

Trade Name

Carvedilol Labetalol Desired effects with nursing implications:

Coreg (alpha-1 and beta-2) Normodyne, Trandate (alpha-1 and beta-2) Produces decreases in BP; alpha- and beta-adrenergic inhibition increases PR and QT intervals, decreases sinus rate, and decreases peripheral vascular resistance; also, with alpha and beta blockade elevated plasma renins are reduced; assess apical and radial pulses before administration and notify physician of any significant changes; baseline parameters of renal and liver function are needed before therapy begins. Dizziness, fatigue, weakness, insomnia, ataxia, hyperesthesia, paresthesia, vertigo, depression; bradycardia, postural hypotension, dependent edema, peripheral edema, A-V block, hypertension or hypotension, palpitations, peripheral ischemia, CHF, pulmonary edema Mild to moderate hypertension; treatment of severe hypertension (IV); severe ventricular tachycardia, supraventricular tachycardia, atrial fibrillation, ventricular fibrillation not controlled by first-line agents, cardiac arrest Alpha and beta blockers cannot be discontinued abruptly; to do so can cause life-threatening arrhythmias and hypertension.

Side effects:

Treatment:

Nursing implications:

◆ Alpha-Adrenergic Blockers Generic Name

Trade Name

Clonidine Alfuzosin Prazosin Terazosin Phentolamine

Catapres Uroxatral Minipress Hytrin Rogitine (continued)

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◆ Chapter 2

◆ Alpha-Adrenergic Blockers (continued) Generic Name

Trade Name

Doxazosin Tamsulosin Desired effects:

Cardura Flomax Reduce total peripheral resistance through alpha blockade; do not affect cardiac output or heart rate; lower blood pressure and decrease cardiac preload (diastolic) and afterload (systolic); blood pressure must be taken before administration of alpha-adrenergic blockers. Dizziness, fatigue, weakness, insomnia, ataxia, hyperesthesia, paresthesia, vertigo, depression; bradycardia, postural hypotension, dependent edema, peripheral edema, A-V block, hypertension, palpitations, peripheral ischemia, CHF, pulmonary edema Hypertension, used alone or as part of combination therapy

Side effects:

Treatment:

Note: Rogitine is used to treat hypertension associated with pheochromocytoma or other adrenergic excess, such as administration of phenylephrine or consumption of tyramine-containing foods in clients using MAOI therapy.

◆ Sympatholytic Central-Acting Alpha-Adrenergic Inhibitors These central-acting antiadrenergic agents are drugs that act within the CNS to reduce the firing of sympathetic neurons.

Generic Name

Trade Name

Clonidine Methyldopa Guanabenz Desired effect:

Catapres Aldomet Wytensin Competitively block postsynaptic alpha-1 receptors, decreasing sympathetic tone of the vascular system, dilating blood vessels and thus lowering arterial BP Drowsiness, sedation, orthostatic hypotension, weakness, dizziness, tachycardia, bradycardia, arrhythmias, CHF, angina, dry mouth, constipation Hypertension used alone or as part of combination therapy; used to reduce blood pressure in situations in which hypertension is due to adrenergic excess by decreasing sympathetic outflow, such as pheochromocytoma

Major side effects: Treatment:

Note: These are no longer used to treat essential hypertension because they also block presynaptic alpha-2 receptors that are believed to mediate a feedback inhibition of further norepinephrine release; this accentuates the reflex tachycardia caused by the lowering of BP.

◆ Adrenergic Neuron Blockers Generic Name

Trade Name

Adrenergic neuron blocking agents are drugs that act presynaptically to reduce the release of norepinephrine from sympathetic neurons. Guanethidine monosulfate Ismelin

Peripheral Nervous System Agents ◆ 19

◆ Adrenergic Neuron Blockers (continued) Generic Name

Trade Name

Reserpine Guanadrel sulfate Desired effect: Side effects: Treatment: Nursing implications:

No commonly used trade name Hylorel Reduce blood pressure Hypotension, bradycardia, nasal congestion Hypertension Reserpine can produce severe depression that may persist for months after the drug is withdrawn. Ismelin may cause impotence, nocturia, urinary incontinence, and inhibition of ejaculation. Hylorel may cause fatigue, faintness, drowsiness, visual disturbances, paresthesias, confusion, and psychological problems.

◆ Angiotensin II Receptor Blockers Generic Name

Trade Name

Candesartan Losartan Irbesartan Telmisartan Valsartan Olmesartan Eprosartan Treatment:

Atacand Cozaar Avapro Micardis Diovan Benicar Teveten Hypertension, alone or in combination with other antihypertensive agents, particularly diuretics and calcium channel blockers Blocks the vasoconstrictor and aldosterone-producing effects of angiotensin II at various receptor sites, including vascular smooth muscle cells and the adrenal glands Lowering of blood pressure Headache, dizziness, syncope, muscle weakness, hypotension, fever, gout, rash, inflammation, urticaria, pruritus, alopecia, dry skin, diarrhea, abdominal pain, nausea, constipation, dry mouth, dental pain Administer without regard to meals; ensure that the patient is not pregnant before beginning therapy; suggest the use of barrier birth control while using olmesartan (Benicar); fetal injury and deaths have been reported; find an alternate method of feeding the infant if given to a nursing mother; depression of the renin-angiotensin system in infants is potentially very dangerous; alert the surgeon and mark the patient’s charts with a notice that olmesartan (Benicar) is being taken; blockade of the renin-angiotensin system following surgery can produce problems; hypotension may be reversed with volume expansion

Desired effects:

Therapeutic effect: Side effects:

Nursing implications:

Chapter

3

Central Nervous System Agents

DRUGS FOR PARKINSON’S DISEASE NURSING IMPLICATIONS 1. Parkinson’s disease is a neurological disorder characterized by disturbance of movement. In Parkinson’s disease, there is an imbalance between dopamine and acetylcholine. 2. Dopamine is an inhibitory transmitter in the brain. Acetylcholine is an excitatory transmitter. 3. By suppressing discharge of the cholinergic neurons, the dopaminergic neurons can prevent excessive excitation. 4. Movements are normal when the excitatory effects of acetylcholine are balanced by the inhibitory influence of dopamine. 5. Movement disorders similar to those of Parkinson’s disease can occur as side effects of therapy with antipsychotic agents. 6. These dyskinesias, which are referred to as extrapyramidal side effects, result from the blockade of dopamine receptors in the striatum.

20

Central Nervous System Agents

◆ 21

7. Sinemet (carbidopa/levodopa) is the drug of choice for treating Parkinson’s disease.1 8. Full therapeutic response may take several months to develop. The client should be informed that beneficial effects are likely to increase steadily over the first few months. 9. In contrast to the dramatic improvement seen during initial therapy, long-term therapy with Sinemet has been disappointing. Although symptoms may be well controlled during the first 2 years of treatment, by the end of 5 years, the client’s ability to function may deteriorate to pretreatment levels.

◆ Drugs for Parkinson’s Disease Generic Name

Trade Name

Carbidopa/levodopa Levodopa Carbidopa Tolcapone Desired effect:

Sinemet No commonly used trade name No commonly used trade name No commonly used trade name Unlike dopamine, levodopa penetrates the blood–brain barrier; it relieves the symptoms of parkinsonism but not drug-induced extrapyramidal disorders. Urinary retention, urinary incontinence, involuntary movements, increased hand tremors, weakness, agitation, anxiety, psychiatric problems, insomnia, nightmares, orthostatic hypotension, tachycardia, hypertension, and alopecia Treatment of parkinsonian syndrome; not useful for drug-induced extrapyramidal reactions. Arrange to decrease dosage if therapy is interrupted; observe for the development of suicidal tendencies; give with meals if GI upset occurs; ensure that the patient voids before receiving a dose if urinary retention is a problem.

Major side effects:

Treatment: Nursing implications:

Notes: Administer only after an MAOI has been discontinued for 2 weeks. If previously on levodopa, discontinue for at least 8 hours before changing to Sinemet. Tolcapone is typically administered with levodopa, prolonging the effects of the latter drug and reducing the overall quantity of medications a client must take. The two together provide more consistent control of movement and speech.

1

Having no therapeutic effects of its own, carbidopa is almost always administered with levodopa in a single formulation containing both drugs. Available as tablets or sustained-release capsules, this combination is marketed under the trade name Sinemet. Levodopa has therapeutic effects when administered alone and may be prescribed.

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◆ Anticholinergic Antiparkinsonism Agents Generic Name

Trade Name

Amantadine Benztropine Bromocriptine Trihexyphenidyl Pergolide mesylate Entacapone Desired effect: Major side effects:

Symmetral Cogentin Parlodel Apo-Trihex (Canada) Permax Comtan Relief of tremors and rigidity in parkinsonian syndrome Dizziness, nervousness, blurred vision, mydriasis (dilation of pupils), dry mouth, and constipation Parkinson’s disease (Cogentin, Apo-Trihex, and diphenhydramine can also be used to decrease the side effects of antipsychotic drugs [e.g., Haldol].) Drug-induced parkinsonism is a parkinsonlike disease induced by use of antipsychotic drugs and characterized by bradykinesia masklike face, drooling, tremors, pill-rolling motions, rigidity, shuffling gait, stooped posture, dyskinesia, sedation, blurred vision, nausea, vomiting, headache, photosensitivity, constipation, hypotension, urinary retention, impotence, breast engorgement and sometimes lactation in both women and men, amenorrhea, and glaucoma

Treatment:

Nursing implications:

◆ Antiseizure Agents Generic Name

Trade Name

Phenobarbital (PO, IV, and IM) Phenytoin sodium Carbamazepine Diazepam Gabapentin Valproic acid Divalproex Treatment: Desired effect:

No commonly used trade name Dilantin (can also be used to treat digitalis-induced dysrhythmias; Dilantin can only be mixed with normal saline.) Tegretol Valium Neurontin Depakene Depakote Seizures Diminished seizure activity

Central Nervous System Agents

◆ 23

◆ Antiseizure Agents (continued) Generic Name

Trade Name

Major side effects with nursing implications:

Tegretol: drowsiness, ataxia, bone marrow suppression, aplastic anemia Dilantin: gingival hyperplasia; pink, red, or reddish-brown discoloration of urine; male sexual dysfunction Depakene: hepatotoxicity, prolonged bleeding; may potentiate the effects of warfarin (Coumadin) Depakote may cause a life-threatening pancreatitis, hepatic failure, depression, psychosis, aggression, hyperactivity, behavioral deterioration, and weakness. Confusion has occurred between the use of delayed-release Depakote and Depakote ER; dosing of the two agents is very different and serious adverse effects can occur, so use extreme caution; Dilantin and Valium cannot be mixed with other drugs; antiseizure drugs may also be used as mood stabilizers.

Nursing implications:

Notes: Tegretol can only be administered by mouth. Tegretol is also used for manic-depressive illness, schizoaffective illness, alcohol withdrawal, and its antidiuretic effect in diabetics.

DRUGS USED TO TREAT SPASTICITY r The term spasticity refers to a group of movement disorders of CNS origin. r These disorders are characterized by heightened muscle tone, spasm, and loss of dexterity.

r The most common causes of spasticity are multiple sclerosis and cerebral palsy. r Other causes include traumatic spinal cord lesions and stroke. r Spasticity is managed with a combination of drugs and physical therapy. ◆ Drugs Used to Treat Spasticity Generic Name

Trade Name

Baclofen Dantrolene Diazepam Desired effect: Major side effects: Treatment:

Lioresal Dantrium Valium Act directly on muscles to cause reduction of muscle spasticity Dizziness, drowsiness, lethargy, hypotension, fatigue Spasticity

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PSYCHOTHERAPEUTIC AGENTS ◆ Antipsychotic Agents Used to Treat Schizophrenia Generic Name

Trade Name

Chlorpromazine Clozapine Fluphenazine Haloperidol Loxapine Molindone Mesoridazine Thioridazine Thiothixene Perphenazine Risperidone Olanzapine Quetiapine Desired effect:

Thorazine (discolors urine pink to reddish-brown) Clozaril Prolixin Haldol Loxitane Moban Serentil Mellaril Navane Trilafon Risperdal Zyprexa Seroquel Schizophrenia is the most common indication for antipsychotic drugs; they suppress symptoms during acute psychotic episodes and, when taken chronically, can greatly decrease the risk of relapse; initial antidepressant effects are seen in 1–2 days, but full effects develop gradually over 6–8 weeks. One of the many side effects these drugs can produce is the extrapyramidal reaction, especially dyskinesia (slow, rhythmic, automatic stereotyped movements, either generalized or in single muscle groups). They are used to treat acute and chronic psychosis and for sedation (the most common psychosis is schizophrenia). Symptoms developing within the first month of therapy are indistinguishable from those of idiopathic Parkinson’s disease. Because of these neurological side effects, the traditional antipsychotics are known alternatively as neuroleptics. Extrapyramidal reactions (pseudoparkinsonism) are treated with antiparkinsonian drugs such as Cogentin or Artane; they must be gradually discontinued over a 3-month period. When these medications are administered IM, symptoms are usually controlled within 48–70 hours, and then oral medications can be given. Monitor the elderly for dehydration, and institute remedial measures promptly; sedation and decreased thirst related to CNS effects can lead to dehydration.

Major side effects:

Treatment:

Nursing implications:

Central Nervous System Agents

◆ 25

◆ Antipsychotic Agents Used to Treat Schizophrenia (continued) Generic Name

Trade Name Educate the patient and family about the need for blood tests weekly or once a month as ordered by the physician; the dosage may be increased gradually to achieve the most effective dose; tell the patient to not take more than the prescribed dosage; do not make up a missed dose, instead contact a heath care provider; do not stop taking these drugs suddenly; gradual reduction of dosage is needed to prevent side effects; educate the patient and family about the side effects of the drug (e.g., drowsiness, seizure, dizziness, syncope, headache, tremor, and agitation).

ANTIDEPRESSANTS These agents fall into the following four major groups: 1. Tricyclic antidepressants 2. Monoamine oxidase inhibitors (MAOIs) 3. Selective serotonin reuptake inhibitors (SSRIs) 4. Miscellaneous antidepressants

TRICYCLIC ANTIDEPRESSANTS The tricyclic antidepressants are drugs of first choice for many clients with major depression.

◆ Tricyclic Antidepressants Generic Name

Trade Name

Amitriptyline (onset 2–3 weeks) Imipramine (onset 1 hour) Amoxapine Desipramine Doxepin

Elavil Tofranil Asendin Norpramin Triadapin (Canada), Zonalon (Canada) (continued)

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◆ Chapter 3

◆ Tricyclic Antidepressants (continued) Generic Name

Trade Name

Nortriptyline Protriptyline Desired effects: Side effects:

Pamelor, Aventyl Triptil (Canada), Vivactil Relief of symptoms of depression Sedation and anticholinergic (atropinelike) effects (dry mouth, blurred vision, increased intraocular pressure), confusion (especially in the elderly), disturbed concentration, hallucinations, disorientation, anxiety, nervousness, restlessness, agitation, panic, insomnia, nightmares, orthostatic hypotension or hypertension, syncope, tachycardia, MI, arrhythmias, heart block; hematologic: bone marrow depression, including thrombocytopenia and leukopenia Relief of symptoms of depression (endogenous depression is most responsive); sedative effects may help depression associated with anxiety and sleep disturbance Alleviate mood, increase activity and alertness, decrease morbid preoccupation, improve appetite, and normalize sleep patterns Drug should not be administered to patients with a history of hypersensitivity to any tricyclic drug, recent MI, myelography within the previous 24 hours or scheduled within 48 hours, pregnancy, lactation, preexisting cerebrovascular disorders, angle-closure glaucoma, increased intraocular pressure, urinary retention, seizure disorders, hyperthyroidism, impaired liver or renal function, psychiatric patients; limit drug access to depressed and potentially suicidal patients.

Treatment:

Desired effects: Nursing implications:

MONOAMINE OXIDASE INHIBITORS (MAOIS) r The combination of a tricyclic antidepressant (e.g., Elavil, Tofranil) and an MAOI can lead to severe hypertension due to excessive adrenergic stimulation of the heart and blood vessels. Therefore, combined therapy with tricyclic antidepressants and MAOIs is generally avoided.

◆ Monoamine Oxidase Inhibitors MAOIs are not used as frequently today because newer drugs with fewer side effects are now available.

Generic Name

Trade Name

Isocarboxazid Phenelzine Tranylcypromine

Marplan Nardil Parnate

Central Nervous System Agents

◆ 27

◆ Monoamine Oxidase Inhibitors (continued) Generic Name

Trade Name

Desired effect: Major side effects:

Relief of depression Orthostatic hypotension, hypertensive crisis from dietary tyramine; avoid foods that contain tyramine, a substance that promotes the release of norepinephrine from sympathetic nerves; tyramine is found in practically all cheeses, avocados, figs, dried or smoked fish, brewer’s yeast extracts, beer, wine, pickled herring, and chicken liver. MAOIs are second- or third-line antidepressants for most clients. Although these drugs are as effective as the tricyclics, they are more dangerous. Antidepressant effect starts at 1–4 weeks and peaks at 3–4 weeks. Monitor BP and orthostatic BP carefully; arrange for a more gradual increase in dosage initially in patients who show a tendency toward hypotension. Arrange for periodic liver function tests during therapy; discontinue drug at the first sign of hepatic dysfunction or jaundice.

Treatment: Nursing implications:

SELECTIVE SEROTONIN REUPTAKE INHIBITORS (SSRIS) r These drugs produce selective blockade of serotonin reuptake. r These drugs are as effective as the tricyclic antidepressants and appear to be safer, although possible long-term effects are not yet known.

◆ Selective Serotonin Reuptake Inhibitors Generic Name

Trade Name

Paroxetine Fluoxetine Sertraline Trazodone Escitalopram Desired effect: Side effects:

Paxil Prozac Zoloft Desyrel Lexapro Relief of depression SSRIs should not be combined with MAOIs since severe adverse effects have been reported. MAOIs should be withdrawn at least 14 days before beginning to take SSRIs. Clients should be instructed that SSRIs and MAOIs take about 4 weeks to produce a steady-state plasma drug level. Side effects include insomnia, sexual dysfunction, nervousness, weight loss, painful menstruation, and anxiety. Major depression; most effective in patients with major depressive disorder; obsessive-compulsive disorder, posttraumatic stress disorder, social anxiety, generalized anxiety disorder, panic disorder

Treatment:

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◆ Chapter 3

◆ Miscellaneous Antidepressants Generic Name

Trade Name

Amoxapine Bupropion Maprotiline Desired effect: Major side effects:

Asendin Wellbutrin, Zyban Ludiomil Relief of depression that will occur slowly over several weeks Drowsiness, sedation, lethargy, dry mouth, dry eyes, blurred vision, and hypotension; Asendin may cause extrapyramidal reactions or tardive dyskinesia. Wellbutrin and Ludiomil may cause seizures. Treatment of depression and anxiety associated with depression; aid to smoking cessation (Zyban) Take drug in equally divided doses three to four times a day as prescribed for depression. Avoid or limit the use of alcohol while on this drug; seizures can occur if these are combined. May be used with transdermal nicotine; most effective for smoking cessation if combined with behavioral support program

Treatment: Nursing implications:

BIPOLAR DISORDER Bipolar disorder is mania and depression separated by periods in which mood is normal. The mainstay of therapy is lithium.

NURSING IMPLICATIONS OF LITHIUM THERAPY r It is important that sodium levels remain normal. Clients should be instructed to maintain normal sodium intake; a sodium-free diet cannot be used. Since diuretics promote sodium loss, these agents must be employed with caution. Sodium loss secondary to diarrhea can be sufficient to cause lithium accumulation, and the patient should be warned of this possibility.

r Measurement of plasma lithium levels is an essential feature of treatment.

DRUG THERAPY FOR BIPOLAR DISORDER ◆ Drugs for Bipolar Disorder Generic Name

Trade Name

Carbamazepine Valproic acid Lithium Desired effect:

Tegretol Depakene No commonly used trade name Control manic episodes; for many clients, adjunctive therapy with a benzodiazepine (e.g., diazepam) or an antipsychotic agent can be helpful.

Central Nervous System Agents

◆ 29

◆ Drugs for Bipolar Disorder (continued) Generic Name

Trade Name

Side effects:

Adverse effects that occur when lithium levels are excessive include abdominal bloating, GI upset, diarrhea, muscle weakness, hypotension, slurred speech, and oliguria. Adverse effects that occur at therapeutic drug levels include fatigue, muscle weakness, headache, confusion, memory impairment, and leukocytosis (10,000–18,000 WBCs/mm3 ). Carbamazepine and valproic acid side effects and their use in seizure disorder are discussed in the section on antiseizure agents. Bipolar disorder Tell the patient that a complete blood count should be obtained prior to treatment, and annually or more frequently if so ordered by the health care provider.

Treatment: Nursing implications:

Note: Carbamazepine (Tegretol) and valproic acid (Depakene) were originally developed and marketed to treat seizure disorders. In recent years lithium has been used with success to treat clients with bipolar disorder. Carbamazepine (Tegretol) is reserved for clients who fail to respond to lithium or who cannot tolerate lithium’s side effects. Tegretol is also used for treatment of alcohol withdrawal symptoms.

DRUGS USED TO TREAT ANXIETY AND INSOMNIA NURSING IMPLICATIONS 1. Anxiety and insomnia are common client complaints, and the drugs employed for treatment are widely prescribed. 2. Drugs that promote sleep are referred to as hypnotics. 3. The distinction between antianxiety effects and hypnotic effects is frequently a matter of dosage; some drugs relieve anxiety in low dosages and induce sleep in high doses. 4. Therefore, a single drug may be considered both an antianxiety agent and a hypnotic agent, depending on the reason for its use and the dosage employed. 5. Some drugs are specifically for insomnia and some are specifically for anxiety. 6. Benzodiazepines are drugs of first choice for treating anxiety and insomnia. 7. In addition, these agents are used to induce general anesthesia and manage seizure disorders, muscle spasms, panic disorder, and withdrawal from alcohol. 8. The most frequently prescribed benzodiazepines are diazepam (Valium), lorazepam (Ativan), and alprazolam (Xanax). 9. The popularity of the benzodiazepines as sedatives and hypnotics stem from their clear superiority over the alternatives (barbiturates and other general CNS depressants). 10. Benzodiazepines are safer than the general CNS depressants and have a lower potential for abuse.

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◆ Chapter 3

BARBITURATES USED TO TREAT INSOMNIA NURSING IMPLICATIONS 1. These drugs cause relatively nonselective depression of CNS function and are the prototypes for the general CNS depressants (e.g., Nembutal, Seconal). 2. Because they depress multiple aspects of CNS function, barbiturates can be used for daytime sedation, induction of sleep, suppression of seizures, and general anesthesia. 3. Barbiturates cause tolerance and dependence, have high abuse potential, and are subject to multiple drug interactions. 4. Because of these undesirable properties, the barbiturates, which were once used widely, have been largely replaced by newer and safer drugs, primarily the benzodiazepines. 5. However, although their use has declined greatly, barbiturates still have important applications in seizure control and anesthesia.

◆ Barbiturates Used to Treat Insomnia Generic Name

Trade Name

Amobarbital Pentobarbital Secobarbital Aprobarbital Desired effect: Treatment of: Side effects:

Amytal Nembutal Seconal Alurate Sedative, hypnotic effect Insomnia; short term as a preoperative sedative Drowsiness, lethargy, respiratory depression, laryngospasm (spasm of laryngeal muscles), hangover, hypotension

◆ Benzodiazepines Used to Treat Insomnia Generic Name

Trade Name

Flurazepam Temazepam Triazolam Desired effect: Side effects:

Dalmane Restoril Halcion Relief of insomnia Dizziness, daytime drowsiness, lethargy, hangover, confusion, mental depression, psychological dependence Insomnia

Treatment:

Central Nervous System Agents

◆ 31

◆ Benzodiazepines Used to Treat Anxiety Generic Name

Trade Name

Zanamivir Alprazolam Chlordiazepoxide Diazepam Lorazepam Midazolam Oxazepam Desired effect: Side effects: Treatment:

Relenza Xanax Librium Valium Ativan Versed Serax, Novoxapam Sedation and relief of anxiety Dizziness, drowsiness, lethargy, blurred vision, apathy, depression, restlessness Anxiety

Note: Versed is frequently used preoperatively because of its amnestic effect and because it can be combined with many other preoperative drugs. The sedative/hypnotic drugs listed above cannot be combined with other drugs.

◆ Nonbarbiturate Sedative/Hypnotic Drugs Used to Treat Insomnia Generic Name

Trade Name

Zaleplon Quazepam Chloral hydrate Zolpidem Zaleplon Desired effects: Major side effects:

Sonata Doral No common trade name Ambien Sonata Sedative and hypnotic Headache, depression, drowsiness, somnolence, abnormal vision, lack of coordination, short-term memory impairment Short-term treatment of insomnia Cannot be administered to patients with hypersensitivity to zaleplon (Sonata), impaired hepatic or respiratory function, pregnancy, labor or delivery, lactation, depression • Doral Sedative and hypnotic effects Transient, mild drowsiness initially; sedation; depression; lethargy; apathy; fatigue; light-headedness; disorientation; restlessness; confusion Ensure that the patient is not pregnant before use; recommend the use of barrier contraceptives. Monitor liver and kidney function, and CBC during long-term therapy.

Treatment: Nursing implications:

Desired effects: Side effects:

Nursing implications:

(continued)

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◆ Chapter 3

◆ Nonbarbiturate Sedative/Hypnotic Drugs Used to Treat Insomnia (continued) Generic Name

Trade Name

Treatment:

Insomnia characterized by difficulty in falling asleep, frequent nocturnal awakenings, or early morning awakening; recurring insomnia or poor sleeping habits; acute or chronic medical situations requiring restful sleep • Chloral hydrate Sedative and hypnotic effects Somnambulism (sleep walking), disorientation, incoherence, paranoid behavior, excitement, delirium, drowsiness, staggering gait, ataxia, light-headedness, vertigo, nightmares, malaise, mental confusion, headache, hallucinations Nocturnal sedation; preoperative sedation to lessen anxiety and induce sleep without depressing respiration or cough reflex Use cautiously with impaired liver or kidney function, depression, or suicidal tendencies • Ambien Sedative and hypnotic effects Amnesia, daytime drowsiness, dizziness, “drugged” feeling, diarrhea, nausea, vomiting, hypersensitivity reactions, physical and psychological dependence Short-term treatment of insomnia Assess mental status and sleep patterns and potential for abuse prior to administering this medication. Storage in tight container in cool environment. Teach patients to avoid alcohol ingestion. Assess for depressant use; serious CNS depression may result.

Desired effects: Side effects:

Treatment: Nursing implications:

Desired effects: Side effects: Treatment of: Nursing implications:

DRUGS USED TO TREAT PAIN r The term narcotic has had so many definitions, it can no longer be used with any precision.

r The term opiate is more specific and applies only to compounds contained in opium (e.g., morphine, codeine).

◆ Narcotic Analgesics (Act as Agonists at Specific Opioid Receptors) Generic Name

Trade Name

Butorphanol Hydromorphone

Stadol Dilaudid

Central Nervous System Agents

◆ 33

◆ Narcotic Analgesics (Act as Agonists at Specific Opioid Receptors) (continued) Generic Name

Trade Name

Meperidine Methadone Codeine Morphine Nalbuphine Desired effects:

Demerol Dolophine, Methadone HCl Intensol, Methadose No commonly used trade name No trade name Nubain These narcotic analgesics act at opioid receptors in the CNS to produce analgesia, euphoria, and sedation; they also act in the medullary cough center to depress cough reflex. Sedation, confusion, hallucinations, dysphoria, hypotension, urinary retention Moderate to severe pain, sedative prior to surgery Morphine is used in management of severe pain, management of pulmonary edema, and relief of pain associated with myocardial infarction. Methadone is also used for detoxification and temporary maintenance treatment of narcotic addiction (it is ineffective for relief of general anxiety). Morphine is the prototype of the strong opioid analgesics and remains the standard by which newer opioids are measured. Morphine and other opioids are subject to abuse, mainly because of their ability to cause pleasurable experiences (e.g., euphoria and sedation).

Side effects: Treatment: Nursing implications:

◆ Narcotic Antagonist Generic Name

Trade Name

Naloxone Treatment:

Narcan Overdose of opioid (narcotic) agents

DRUGS USED TO TREAT HEADACHES r Drug selection depends on the intensity of the attack. For mild to moderate symptoms, aspirin, acetaminophen, or ibuprofen may be sufficient.

r If this is inadequate, aspirin combined with codeine may be tried. r If these analgesics prove insufficient, an ergot alkaloid (either ergotamine or dihydroergotamine) may be used.

r If these agents fail to relieve pain, an opioid (narcotic) analgesic (e.g., meperidine [Demerol]) may be needed.

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◆ Antimigraine Agents Generic Name

Trade Name

Ergotamine Dihydroergotamine Sumatriptan Valproic acid Rizatriptan Naratriptan Zolmitriptan Eletriptan Almotriptan Frovatriptan Valdecoxib Desired effect:

No commonly used trade name No commonly used trade name Imitrex Depakene Maxalt Amerge Zomig Relpax Axert Frova Bextra Constriction of dilated carotid artery bed with resolution of vascular headache Abdominal pain, muscle pain, extremity stiffness, stiff neck, stiff shoulders, leg weakness, numbness or tingling in fingers or toes Contraindicated in peripheral vascular disease, cardiovascular disease, hypertension, pregnancy Migraine headaches

Side effects: Nursing implications: Treatment:

◆ Drugs Used to Treat Alzheimer’s Disease Generic Name

Trade Name

Galantamine Donepezil Tacrine Rivastigmine Desired effects:

Reminyl Aricept Cognex Exelon Oral Solution These drugs are centrally acting reversible cholinesterase inhibitors leading to elevated acetylcholine levels in the cortex, which slows the neuronal degradation that occurs in Alzheimer’s disease. Headache, fatigue, dizziness, confusion, ataxia, insomnia, somnolence, tremor, agitation, depression, anxiety, abnormal thinking Name confusion has occurred between Aricept (donepezil) and Aciphex (rabeprazole); use caution. Name confusion has also occurred between tacrine and Tequin (gatifloxacin); use caution. Mild to moderate dementia of the Alzheimer’s type

Side effects: Nursing implications:

Treatment:

Chapter

4

Drugs that Affect Fluid and Electrolyte Balance

DIURETICS NURSING IMPLICATIONS 1. Diuretics are drugs that increase the output of urine. These agents have one major application: the mobilization of edematous fluid associated with hypertension, heart failure, cirrhosis, and kidney disease. 2. High-ceiling (loop) diuretics are the most effective diuretics available. These drugs produce greater loss of fluid and electrolytes than other diuretics because their site of action is in the loop of Henle. 3. Furosemide (Lasix) is especially useful in patients with severe renal impairment, since unlike the thiazides, this drug can promote diuresis even when renal blood flow and glomerular filtration rates are low. Thiazides have little or no direct effect on glomerular filtration rate, whereas Lasix exhibits a renal vasodilator effect, resulting in less vascular resistance and increased renal blood flow. Lasix is therefore useful in renal failure, although it is contraindicated in anuria (absence of urine formation).

35

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THIAZIDES Nursing Implications Thiazide diuretics (also known as benzothiadiazides) have effects similar to those of the loop diuretics. Like the loop diuretics, thiazides increase renal excretion of sodium, chloride, potassium, and water. In addition, thiazides elevate plasma levels of uric acid and glucose. The principal difference between the thiazides and the loop diuretics is that the maximum diuresis produced by the thiazides is considerably lower than the maximum diuresis produced by the high-ceiling agents.

◆ High-Ceiling (Loop) Diuretics Generic Name

Trade Name

Furosemide Ethacrynic acid Bumetanide Desired effect:

Lasix Edecrin Bumex Diuresis and subsequent mobilization of excess fluid (edema, pleural effusion); lower blood pressure Dehydration, hypotension, hypokalemia, hyponatremia, metabolic alkalosis, hypomagnesemia Pulmonary edema associated with congestive heart failure, edema of cardiac, hepatic, or renal origin that has been unresponsive to less effective diuretics

Side effects: Treatment:

Note: Lasix given IV too rapidly will cause hearing loss.

◆ Thiazides Generic Name

Trade Name

Chlorothiazide Hydrochlorothiazide Hydroflumethiazide Methyclothiazide Trichlormethiazide Benzthiazide Metolazone Desired effect:

Diuril HydroDIURIL Diucardin, Saluron Enduron Diurese, Trichlorex (Canada) Exna Mykrox, Zaroxolyn Lowering of blood pressure in hypertensive patients and diuresis with subsequent mobilization of edema

Drugs that Affect Fluid and Electrolyte Balance ◆ 37

◆ Thiazides (continued) Generic Name

Trade Name

Side effects:

Hypokalemia, hyperuricemia, hypotension, hyperglycemia, hypochloremia, hyponatremia, hypomagnesemia; metolazone also has the following side effects: aplastic anemia, hemolytic anemia, leukopenia, agranulocytosis, neutropenia Alone or in combination with other agents in the management of mild to moderate hypertension; alone or in combination in the treatment of edema associated with congestive heart failure, nephrotic syndrome, or pregnancy

Treatment:

POTASSIUM-SPARING DIURETICS Nursing Implications The potassium-sparing diuretics can elicit two potentially useful responses—an increase in urine production and a decrease in potassium excretion. Because their diuretic effects are limited, the potassium-sparing drugs are employed to counteract potassium loss caused by the loop diuretics and thiazides.

◆ Potassium-Sparing Diuretics Generic Name

Trade Name

Spironolactone Triamterene Amiloride Desired effects:

Aldactone Dyrenium • Midamos Competitively blocks the effects of aldosterone in the renal tubule, causing loss of sodium and water and retention of potassium Dizziness, vertigo, paresthesias, weakness, headache, drowsiness, fatigue, orthostatic hypotension, volume depletion, polyuria, nocturia, impotence, loss of libido Used alone or in combination with other diuretics to treat hypertension and edema caused by any disorder They augment diuresis and help counteract the potassium-wasting effect of the more powerful diuretics (e.g., Lasix, Hydro-DIURIL).

Side effects:

Treatment: Nursing implications:

OSMOTIC DIURETICS Nursing Implications 1. Four compounds, mannitol, urea, glycerin, and isosorbide, are classified as osmotic diuretics. However, of the four, only mannitol is used for its diuretic actions.

38

◆ Chapter 4 2. Mannitol differs from other diuretics both in mechanism of action and clinical application. 3. Mannitol promotes diuresis by creating an osmotic force within the lumen of the nephron. Diuresis begins in 30–60 minutes and persists for 6–8 hours.

◆ Osmotic Diuretics Generic Name

Trade Name

Mannitol Urea Glycerin Isosorbide

No commonly used trade name No commonly used trade name Colace Suppositories No commonly used trade name • Mannitol Mannitol increases the osmotic pressure of the glomerular filtrate, thereby inhibiting reabsorption of water and electrolytes; cause excretion of water, sodium, potassium, chloride, calcium, magnesium urea, and uric acid Transient volume expansion, tachycardia, chest pain, congestive heart failure, pulmonary edema, hyponatremia or hypernatremia, hypokalemia, hypotension, and dehydration; fluid loss in excess of electrolyte excretion may produce hypernatremia or hyperkalemia. Mannitol is used as an adjunct in the treatment of acute renal failure before evidence of permanent renal failure is present; adjunct in the treatment of edema caused by increased intracranial and intraocular pressure and other disorders; reduction of intracranial or intraocular pressure • Urea Elevates the osmolarity of the glomerular filtrate, hindering the reabsorption of water and leading to a loss of water, sodium, and chloride; creates an osmotic gradient in the eye between plasma and ocular fluids, reducing intraocular pressure, and hypotension Dizziness, headache, syncope, nausea, vomiting, thrombophlebitis Reduction of intracranial pressure and treatment of cerebral edema, and reduction of elevated intraocular pressure • Glycerin Elevates the osmolarity of the glomerular filtrate, thereby hindering the reabsorption of water and leading to loss of water, sodium, and chloride; creates an osmotic gradient in the eye between plasma and ocular fluids, thereby reducing intraocular pressure; causes the local absorption of sodium and water in the stool, leading to a more liquid stool and local intestinal movement. Cardiac arrhythmias, confusion, headache, syncope, disorientation, severe dehydration and hypotension

Desired effect:

Side effects:

Treatment:

Desired effects:

Major side effects: Treatment:

Desired effects:

Major side effects:

Drugs that Affect Fluid and Electrolyte Balance ◆ 39

◆ Osmotic Diuretics (continued) Generic Name

Trade Name

Treatment:

Glaucoma, before ocular surgery is performed under local anesthetic when a reduction in intraocular pressure is indicated; temporary constipation, before rectal surgery • Isosorbide Elevates the osmolarity of the glomerular filtrate, hindering the reabsorption of water and leading to a loss of water, sodium, and chloride; creates an osmotic gradient in the eye between plasma, and ocular fluid, reducing intraocular pressure, and hypotension. Headache, confusion, disorientation, dizziness, syncope, hypernatremia, decreased urinary output Glaucoma: To alleviate acute attacks; it poses less risk of nausea and vomiting than other oral osmotic agents; short-term reduction of intraocular pressure before and after ocular surgery

Desired effects:

Major side effects: Treatment:

URINARY TRACT INFECTION ◆ Drugs to Treat Urinary Tract Infection Generic Name

Trade Name

Phenazopyridine Methylene blue Co-trimoxazole Nitrofurantoin Cephalexin

Pyridium Urolene Blue Bactrim, Septra Furadantin, Macrodantin Keflex • Pyridium Pyridium is used for the relief of symptoms of pain and burning; used with urinary anti-infectives Renal and hepatic toxicity, yellow-orange urine, hemolytic anemia, hemolytic anemia, rash, headache Symptomatic relief of pain, urgency, burning, frequency, and discomfort related to irritation of the lower urinary tract mucosa caused by infection, trauma, surgery, or endoscopic procedures. • Urolene Blue Urinary tract anti-infective Dizziness, headache, mental confusion, nausea, vomiting, blue-green stools, discolored urine (blue-green), bladder irritation (continued)

Desired effect: Major side effects: Treatment:

Desired effects: Major side effects:

40

◆ Chapter 4

◆ Drugs to Treat Urinary Tract Infection (continued) Generic Name Treatment:

Desired effect: Side effects: Treatment: Desired effect: Major side effects: Treatment:

Desired effects: Side effects: Treatment:

Trade Name Urolene Blue (continued) Cyanide poisoning and drug-induced methemoglobinemia; GU antiseptic for cystitis and urethritis • Bactrim, Septra Antibacterial Hemolytic anemia, low white blood cell and platelet counts, thrombocytopenia, aplastic anemia (rare), nausea, vomiting Urinary tract infection Furadantin, Macrodantin Urinary tract anti-infective Anorexia, drowsiness, vertigo, pruritus, asthma attack, nausea, vomiting Urinary tract infection caused by susceptible strains of Escherichia coli, Staphylococcus aureus, Klebsiella, Enterobacter, and Proteus spp.; prophylaxis or long-term suppression of UTIs • Keflex Bactercidal: Inhibits synthesis of bacterial cell walls, causing cell death Bone marrow depression, anaphylaxis, pseudomembranous colitis, liver toxicity, dizziness, headache, anorexia, rash, anaphylaxis, diarrhea Respiratory tract infections caused by Streptococcus pneumoniae or group A beta hemolytic streptococci; dermatologic infections caused by staphylococci or streptococci; otitis media caused by S. pneumoniae or Haemophilus influenzae; bone infection caused by staphylococci or Proteus mirabilis; GU infections caused by E. coli or Klebsiella

HYPOTENSIVE AGENTS ◆ Hypotensive Agents Generic Name

Trade Name

Dopamine Epinephrine (adrenaline) Norepinephrine Aramine Desired effects: Major side effects: Treatment:

No commonly used trade name No commonly used trade name Levophed No commonly used trade name Increase blood pressure (cause vasoconstriction and increase heart rate) Nervousness, tachycardia, hypertension, arrhythmias, angina Hypotension, bradycardia, and COPD

Drugs that Affect Fluid and Electrolyte Balance ◆ 41

VOLUME EXPANDERS ◆ Volume Expanders Generic Name

Trade Name

Plasma Albumin Dextran Desired effects:

Plasmanate • Albuminar • Gentran Maintain plasma colloid osmotic pressure and aid intermediate metabolites in the transport and exchange of tissue products; important in the maintenance of normal blood volume Pulmonary edema, fever, chills, nephrotoxicity (with rapid IV infusion), hypertension, hypotension, tachycardia, nausea, vomiting, rash, headache, dyspnea Volume deficit and hypoproteinemia; hemolytic disease in newborns; binds free bilirubin (pending exchange transfusion); hypotension; ascites; severe burns; hypovolemic shock; other causes of severe fluid volume deficit Expansion of plasma volume, increase of protein, maintenance of cardiac output in situations associated with deficiencies in circulatory volume, bring fluid (edema) back into the vascular system, and hold fluid within the vascular system

Side effects:

Treatment:

Desired effect:

Chapter

5

Cardiovascular Drugs

You have already studied many drugs used for cardiovascular disorders in Chapters 2 and 4; refer also to Chapter 6. The new drug classifications presented in this section are: 1. Angiotensin-converting enzyme inhibitors (ACEIs) 2. 3. 4. 5. 6. 7.

Calcium channel blockers Agents that selectively dilate arterioles Nipride, a selective venous and arteriolar dilator Inotropic drugs Sodium channel blockers Organic nitrates

ANGIOTENSIN-CONVERTING ENZYME INHIBITORS 1. Angiotensin-converting enzyme inhibitors (ACEIs) are important drugs for treating hypertension and congestive heart failure. 2. The primary effect of these drugs is vasodilation, resulting from inhibition of the renin-angiotensin-aldosterone system. 42

Cardiovascular Drugs ◆ 43 3. The rate at which renin is released from the kidney determines the amount of angiotensin II and aldosterone formation. 4. Angiotensin II is an extremely potent vasoconstrictor, most prominently in arterioles. When angiotensin II is inhibited, vasodilation occurs. 5. Captopril (Capoten) was the first ACE inhibitor to be widely employed. The drug is administered orally to treat hypertension and congestive heart failure. There are now several other widely used ACEIs (e.g., enalapril [Vasotec]). 6. The pharmacological effects of these drugs result from inhibition of ACE. By inhibiting ACE, the drugs prevent conversion of angiotensin I into angiotensin II, a potent vasoconstrictor, and stimulation of aldosterone release. 7. The major response to reduced angiotensin II production is vasodilation, primarily in arterioles, and to a lesser degree, in veins.

NURSING IMPLICATIONS 1. Reduced aldosterone release (secondary to reduced angiotensin II) promotes renal retention of potassium and increased excretion of sodium and water. 2. ACE inhibitors offer several advantages over other antihypertensive drugs. They can be used safely in patients with bronchial asthma, a condition that precludes the use of beta-adrenergic blocking agents. 3. ACEIs do not promote hypokalemia, hyperuricemia, or hyperglycemia; these side effects are seen in patients using thiazide diuretics. 4. ACEIs do not induce lethargy, weakness, or sexual dysfunction—common responses to the older antihypertensive agents. 5. ACEIs produce multiple benefits in patients with congestive heart failure (CHF). 6. By lowering arteriolar tone, ACEIs improve regional blood flow, and by reducing cardiac afterload, increase cardiac output. 7. By dilating blood vessels in the kidney, the drug increases renal blood flow, thereby promoting excretion of sodium and water.

◆ Angiotensin-Converting Enzyme Inhibitors (ACEIs) Generic Name

Trade Name

Captopril Benazepril HCl Enalapril Trandolapril Enalaprilat Lisinopril

Capoten Lotensin Vasotec Mavik Vasotec I.V. Prinivil, Zestril (continued)

44

◆ Chapter 5

◆ Angiotensin-Converting Enzyme Inhibitors (ACEIs) (continued) Generic Name

Trade Name

Quinapril HCl Ramipril Fosinopril sodium Moexipril Perindopril Desired effect: Major side effects:

Accupril Altrace Monopril Univasc • Aceon Suppression of the renin-angiotensin-aldosterone system First-dose hypotension is most likely in patients with severe hypertension who are taking diuretics and who are volume depleted; persistent, dry, irritating, nonproductive cough; hyperkalemic inhibition of aldosterone release (secondary to inhibition of angiotensin II production) can cause potassium retention by the kidney; as a rule, significant potassium accumulation is limited to patients taking potassium supplements or potassium-sparing diuretics or who are in renal failure. Hypertension and congestive heart failure ACEIs are contraindicated for patients with renal artery stenosis, because their potassium is already above the normal serum level of 3.5–5.0 mEq/L; contraindicated during the second and third trimesters of pregnancy, because potassium is already above normal; ACEIs can increase serum lithium levels, causing toxicity.

Treatment: Nursing implications:

CALCIUM CHANNEL BLOCKERS 1. Calcium channel blockers are drugs that prevent calcium ions from entering cells. These drugs have their greatest effect on the heart and blood vessels. 2. Calcium channel blockers reduce blood pressure by causing vasodilation of peripheral arterioles, arteries, and arterioles of the heart. 3. Over the last decade, the calcium channel blockers have assumed a prominent role in the treatment of hypertension, angina pectoris, and myocardial infarction (MI), as well as cardiac dysrhythmias.

NURSING IMPLICATIONS 1. Calcium channel blockers, beta-adrenergic blockers, and digoxin have two of the same effects—decreased heart rate and decreased A-V conduction. Remember, digoxin not only decreases cardiac rate but also increases the force of cardiac

Cardiovascular Drugs ◆ 45 contractions, thereby increasing cardiac output, and it is also used to treat atrial dysrhythmias. 2. Therefore, the nurse must take the patient’s apical pulse before administering these medications. If the pulse is below 60 beats per minute in adults, the drug is withheld and the physician notified. 3. Beta-adrenergic blockers and calcium channel blockers cause peripheral vasodilation; therefore, blood pressure must also be taken before their administration. 4. The nurse must take the patient’s blood pressure before administering calcium channel blockers or beta-adrenergic blockers because they lower the blood pressure. If the patient’s blood pressure is significantly lower than his or her baseline, hold the medication and notify the physician. For example, if the patient’s baseline blood pressure is 180/100 mm Hg and it is now 110/70 mm Hg, withhold the medication and notify the physician. While the purpose of these drugs is to decrease blood pressure, it should not go below the patient’s normal blood baseline pressure. 5. Calcium channel blockers decrease myocardial contractility, thereby decreasing the workload of the heart; that is why this drug class is used to treat myocardial infarction (MI) and for treatment of arrhythmias.

◆ Calcium Channel Blockers Generic Name

Trade Name

Amlodipine Isradipine Bepridil Diltiazem Felodipine Nicardipine Nifedipine Nimodipine Nisoldipine Verapamil Desired effect: Side effects: Treatment:

Norvasc • DynaCirc, DynaCirc CR Vascor Cardizem, Cardizem CD Plendil Cardene Adalat, Procardia • Nimotop • Sular Calan, Isoptin Decrease angina pain, management of hypertension and arrhythmias Headache, arrhythmias, hypotension, fatigue, dizziness Hypertension, angina, and cardiac arrhythmias

Notes: Calcium channel blockers relax arterial smooth muscle, depress the rate of the sinus node pacemaker, slow A-V conduction, and decrease heart rate. All calcium channel blockers decrease coronary vascular resistance, increase coronary blood flow, and reduce myocardial oxygen demand. Nifedipine should be used with great caution if at all because of the risk of death according to the National Heart, Lung and Blood Institute. Calcium blockers cannot be discontinued abruptly; a physician must be consulted.

46

◆ Chapter 5

VASODILATORS Vasodilation can be produced with a wide variety of drugs. Some of these drugs act primarily on arterioles, some act primarily on veins, and some dilate both types of vessels. 1. Vasodilators are widely used, ranging from the treatment of hypertension to angina pectoris to heart failure. 2. Five vasodilator agents are introduced here: hydralazine (Apresoline), minoxidil (Loniten, Rogaine), diazoxide (Hyperstat IV), nitroprusside (Nipride, Nitropress), and nitroglycerin. 3. All other commonly used cardiovascular vasodilators are discussed in Chapter 2. 4. The selectivity of a vasodilator determines its hemodynamic effects. For example, dilators of resistance vessels (arterioles) cause a decrease in cardiac afterload (the force against which the heart must work to pump blood). 5. By decreasing afterload, arteriolar dilators reduce cardiac work, while at the same time increasing cardiac output and tissue perfusion.

◆ Types of Vasodilators Category

Examples

Angiotensin-converting enzyme inhibitors Organic nitrates

Vasotec, Capoten, Zestril (presented in this chapter)

Calcium channel blockers Alpha-adrenergic blockers Beta-adrenergic blockers Adrenergic neuron blockers Central-acting agents Agents that selectively dilate arterioles Selective venous and arteriolar dilator

Nitroglycerin, Nitro-Bid, Nitrostat, Nitropress (presented in this chapter) Cardizem, Procardia, Calan, Isoptin (presented in this chapter) Catapres, Minipress, Serpasil, Hytrin, Rogitine, Dibenzyline (presented in Chapter 2) Tenormin, Betoptic, Lopressor, Corgard, Inderal, Timoptic (presented in Chapter 2) Reserpine, Ismelin (presented in Chapter 2) Catapres, Aldomet (presented in Chapter 2) Apresoline, Loniten, Hyperstat (presented in this chapter) Nipride (presented in this chapter)

Note: Drugs are listed by the most commonly used name.

Cardiovascular Drugs ◆ 47

◆ Agents that Selectively Dilate Arterioles (Reduce Afterload) Generic Name

Trade Name

Hydralazine Minoxidil Diazoxide

Apresoline Loniten Hyperstat IV (Increase blood glucose) rApresoline Acts directly on vascular smooth muscle to cause vasodilation, primarily arteriolar; maintains or increases renal and cerebral blood flow Headache, palpitations, tachycardia, angina pectoris, anorexia, nausea, vomiting, nasal congestion Oral: Essential hypertension alone or in combination with other agents; Parenteral: Severe essential hypertension when drug cannot be given orally or when the need to lower blood pressure is urgent Educate the patient to take the drug exactly as prescribed; take medication with food; do not discontinue or reduce dosage without consulting the health care provider; advise the patient about the side effects of the medication and to report persistent chest pain, constipation, unexplained fever or malaise, muscle or joint pain, rash, numbness, and tingling. rLoniten Acts directly on vascular smooth muscle to cause vasodilation, reducing elevated systolic and diastolic BP; does not interfere with CV reflexes, but does cause tachycardia and renin release, leading to sodium and water retention. Fatigue, headache, tachycardia (unless given with a beta-adrenergic blocker or other sympatholytic drug); temporary edema, irritant dermatitis, allergic contact dermatitis, eczema, pruritus, dry skin Severe hypertension that is symptomatic or associated with target organ damage and is not manageable with maximum therapeutic doses of a diuretic plus two other antihypertensive drugs; use in milder hypertension is not recommended; topical use for alopecia Advise the patient that if they apply the topical preparation to an affected area, to use the fingers and wash hands thoroughly afterward. Oral: Take this drug exactly as prescribed, and take all other medications that have been prescribed. Do not discontinue any drug or reduce dosage without consulting the health care provider. Educate the patient about signs and symptoms associated with the drug and to report them to the health care provider (e.g., increase in heart rate). rHyperstat Increases blood glucose by decreasing insulin release; decreases BP by relaxing arteriolar smooth muscle MI, angina, CHF (secondary to fluid and sodium retention), cerebral ischemia, thrombocytopenia, hyperglycemia, glycosuria, ketoacidosis and nonketotic hyperosmolar coma, headache, seizures, blurred vision

Desired effect: Major side effects: Treatment:

Nursing implications:

Desired effects:

Major side effects:

Treatment:

Nursing implications:

Desired effects: Major side effects:

(continued)

48

◆ Chapter 5

◆ Agents that Selectively Dilate Arterioles (Reduce Afterload) (continued) Generic Name Treatment:

Nursing implications:

Trade Name Hyperstat (continued) Oral: Management of hypoglycemia due to hyperinsulinism in infants and children, and to inoperable pancreatic islet-cell malignancies; Parenteral: Short-term use in malignant and nonmalignant hypertension; used primarily in hospitals Monitor intake and output and weigh patient daily at the same time to check for fluid retention; have insulin and tolbutamide (an oral antidiabetic agent) readily available in case a hyperglycemic reaction occurs; have dopamine and norepinephrine readily available in case of severe hypotension.

◆ Nipride: A Selective Venous and Arteriolar Dilator (Reduces Afterload and Preload) Generic Name

Trade Name

Nitroprusside Desired effect: Side effects:

Nipride Rapid lowering of blood pressure Retention of sodium and water; Lasix used with Nipride can help offset this effect because two of the side effects of Lasix are dehydration and hyponatremia; if administered too rapidly, Nipride can cause a precipitous fall in blood pressure, resulting in headache, palpitations, nausea, vomiting, and sweating. Drug of choice for treating hypertensive emergencies Blood pressure and heart rate should be monitored frequently; if severe hypotension occurs, drug effects are quickly reversed by decreasing the rate or temporarily discontinuing the infusion; it is also necessary to monitor for rebound hypertension following discontinuation of Nipride; pulmonary capillary wedge pressure (PCWP) is usually monitored in clients with acute CHF or severe hypertension while receiving IV Nipride; plasma cyanide (thiocyanate levels) should be monitored every 48–72 hours; Nipride contains five cyanide groups, which are converted into thiocyanate in the liver; signs and symptoms of cyanide poisoning include rapid respirations, later becoming slow and gasping; choking feeling; anxiety; dizziness; confusion; headache; pulse rapid, feeble, and irregular; if not treated, the patient will become unconscious and die. Treatment for cyanide poisoning includes amyl nitrate inhalation and infusion of sodium nitrate.

Treatment: Nursing implications:

Treatment:

Notes: Reflex tachycardia is minimal. Dilators of veins and arterioles cause a reduction in cardiac preload (the force with which blood is returned to the heart). By decreasing preload, venous dilators cause a decrease in cardiac filling and cardiac workload, along with a decrease in cardiac output and tissue perfusion. (Preload is another name for diastole [e.g., venous blood is returning to the heart]. Afterload is another name for systole [e.g., arterial blood is pumped out of the heart].) Nipride must be covered with a paper bag while being administered.

Cardiovascular Drugs ◆ 49

INOTROPIC AGENTS The cardiac glycosides (e.g., digoxin) are the oldest and most frequently prescribed inotropic drugs (drugs influencing the force of cardiac contraction). Three types of inotropic drugs are available: (1) cardiac glycosides, (2) adrenergic agents [e.g., epinephrine], and (3) phosphodiesterase (PDE) inhibitors (e.g., amrinone).

NURSING IMPLICATIONS The adrenergic agents (catecholamines) and the PDE inhibitors currently available can only be administered intravenously. At this time, the cardiac glycosides are the only inotropic agents that can be used orally. Therefore, these are the only inotropics suited for long-term chronic treatment of CHF.

◆ Cardiac (Digitalis) Glycosides Generic Name

Trade Name

Digoxin Treatment of: Desired effect: Side effects:

Lanoxin Congestive heart failure (CHF) and atrial dysrhythmias Increase the force of ventricular contraction, and thereby increase cardiac output Production of dysrhythmias is the most serious adverse effect of digoxin. The drug causes dysrhythmias by altering the electrical properties of the heart. Digoxin can mimic practically all types of dysrhythmias. A-V block due to digoxin is one of the most common causes of bradycardia. Ventricular flutter and ventricular fibrillation are the most dangerous side effects. Other side effects include fatigue, weakness, blurred vision, yellow vision, and anorexia. The most common cause of dysrhythmias in clients receiving digoxin is hypokalemia secondary to the use of diuretics that are not potassium-sparing; less common causes of hypokalemia include vomiting and diarrhea. Hypokalemia promotes dysrhythmias by increasing digoxin’s ability to increase automaticity of Purkinje fibers. Because low potassium can precipitate dysrhythmias, it is imperative that serum potassium levels be kept within the normal range. If diuretic therapy causes potassium levels to fall, a potassium-sparing diuretic (e.g., spironolactone) can be added to the regimen to correct the problem; potassium supplements may also be used. Patients must be taught to recognize symptoms of hypokalemia (e.g., muscle weakness) and be instructed to notify the physician if these develop. Digoxin has a narrow therapeutic range; drug levels only slightly higher than the therapeutic level greatly increase the risk of toxicity. If plasma digoxin levels are monitored and kept within the therapeutic range, the chances of dysrhythmia will be reduced. For digoxin, the usual therapeutic range is 0.05–2.0 ng/mL; levels above 2.5 ng/mL are toxic; do not confuse this with the loading dose, which is 0.75–1.25 mg PO.

Nursing implications:

(continued)

50

◆ Chapter 5

◆ Cardiac (Digitalis) Glycosides (continued) Generic Name

Trade Name

Amrinone Milrinone Treatment of:

Inocor Primacor Treatment of CHF in patients who have not responded to digoxin,diuretics, and vasodilators; Inocor or Primacor are indicated for short-term (2–3 days) treatment of CHF. Increase in myocardial contractility and promotion of vasodilation; comparative studies indicate that improvement in cardiac function elicited by Inocor and Primacor are superior to those elicited by dopamine or dobutamine. Like dopamine and dobutamine, Inocor and Primacor are administered by intravenous infusion, and therefore are not suitable for outpatient use.

Desired effect:

Nursing implications:

Notes: Remember, adrenergic agents used for inotropic effects (e.g., increase in the force of cardiac contractions) are covered in Chapter 2. Phosphodiesterase inhibitors are also inotropic agents; see later in this chapter. Take apical pulse before administration of digoxin. Do not give if pulse is below 60 beats per minute and call a physician.

DRUGS FOR DYSRHYTHMIAS SODIUM CHANNEL BLOCKERS Quinidine is the oldest and most thoroughly studied sodium channel blocker. By blocking sodium channels, quinidine slows impulse conduction in the atria, ventricles, and His-Purkinje system. In addition, the drug delays repolarization of these sites. Both actions contribute to suppression of dysrhythmias. Quinidine is strongly anticholinergic (atropinelike) and blocks vagal input to the heart.

◆ Sodium Channel Blockers Generic Name

Trade Name

Quinidine Treatment of:

No commonly used trade name The principal indication for quinidine is long-term suppression of dysrhythmias, including supraventricular tachycardia, atrial flutter, atrial fibrillation, and sustained ventricular tachycardia. Diarrhea, hypotension, tinnitus (ringing in the ears), headache, vertigo, sinus arrest, and A-V block The ECG will change with quinidine overdose, which will cause cardiotoxicity; important danger signals are widening of the QRS complex and excessive prolongation of the QT interval; the physician should be notified immediately if these changes occur.

Side effects: Nursing implications:

Cardiovascular Drugs ◆ 51

◆ Sodium Channel Blockers (continued) Generic Name

Trade Name

Procainamide Treatment of:

Pronestyl Pronestyl is similar to quinidine in action and applications; like quinidine it is used to treat a broad spectrum of dysrhythmias; unfortunately, serious side effects limit the drug’s use. Prolonged treatment with Pronestyl is associated with severe immunologic reactions; other side effects are hypotension, blood dyscrasias, and cardiotoxicity, indicated on ECG by QRS widening and excessive prolongation of the QT interval. Xylocaine Lidocaine, an intravenous agent, is only used to treat ventricular dysrhythmias; in addition to its antidysrhythmic application, lidocaine is employed as a local anesthetic. Lidocaine is generally well tolerated; however, adverse central nervous system effects can occur. High therapeutic doses can cause drowsiness, confusion, paresthesias, convulsions, hypotension, bradycardia, and heart block. Mexitil Tonocard Mexitil and Tonocard, oral congeners of lidocaine, are used to treat ventricular dysrhythmias and ventricular tachycardia. Same side effects as lidocaine Dilantin Dilantin is an antiseizure drug that is also used to treat digoxin-induced dysrhythmias; Dilantin is presented in Chapter 3 (antiseizure agents); discussion here is limited to its antidysrhythmic applications. Sedation, ataxia, and nystagmus With too rapid IV administration, Dilantin can cause hypotension, dysrhythmias, and cardiac arrest; gingivitis and hyperplasia of the gums is a frequent complication of long-term use; may also cause pink, red, or reddish-brown discoloration of urine.

Side effects:

Lidocaine Treatment of:

Side effects: Nursing implications: Mexiletine Tocainide Treatment: Side effects: Phenytoin Treatment of:

Side effects: Nursing implications:

Note: Dilantin is a second-line drug after lidocaine for treatment of digoxin-induced dysrhythmias.

DRUG THERAPY FOR HYPERTENSION You have already studied the other drugs used for hypertension in prior chapters. This additional information will help you understand the therapeutic regimen used in the treatment of hypertension. Treatment of hypertension has two objectives: to reduce systolic and diastolic blood pressure and to prevent long-term complications. Lifestyle changes can adequately decrease blood pressure in many people, thus eliminating the need for drug therapy.

52

◆ Chapter 5

DIURETICS Diuretics are a mainstay of antihypertensive therapy. These drugs reduce the blood pressure when used alone and they can enhance the effects of other hypotensive agents. Diuretics are presented in Chapter 4.

Thiazide Diuretics 1. Thiazides (e.g., HydroDIURIL) are the most commonly used antihypertensive diuretics. Thiazides reduce blood pressure by two mechanisms: reduction of blood volume and reduction of arterial resistance. 2. High-ceiling loop diuretics: High-ceiling loop diuretics (e.g., Lasix) produce much greater diuresis than thiazides. Like the thiazides, the loop diuretics lower blood pressure by reducing blood volume. Loop diuretics do not promote vasodilation; remember that the thiazides will reduce arterial pressure. 3. Potassium-sparing diuretics: The degree of diuresis induced by potassium-sparing diuretics (e.g., Aldactone) is small. However, these drugs can play an important role in an antihypertensive regimen. Their role is to balance potassium loss cause by thiazide or loop diuretics.

BETA-ADRENERGIC BLOCKERS 1. The beta blockers (e.g., Inderal, Lopressor) are among the most commonly used antihypertensive drugs. Beta-adrenergic blockers are presented in Chapter 2. The beta blockers have at least three useful actions in the treatment of hypertension: a. Blockade of cardiac beta-1 receptors in the heart decreases heart rate and cardiac contractility, thereby decreasing cardiac output. b. When there is peripheral vasodilation, the heart senses hypotension and will compensate with tachycardia. c. Blockage of beta-1 receptors in the kidney reduces the release of renin, thereby reducing vasoconstriction; therefore, vasodilation occurs. Reduced aldosterone reduces sodium and water retention. Both of these actions reduce blood pressure. 2. Beta-adrenergic blockers can produce a variety of adverse effects. Three of the more dangerous effects are: a. Bradycardia b. Decreased atrioventricular (A-V) conduction c. Reduction of cardiac contractility 3. Beta-1 adrenergic blockers should not be used by patients with the following medical problems: a. Sick sinus syndrome b. Congestive heart failure c. Second- or third-degree A-V block Note: Beta-1 receptors are present in the heart.

Cardiovascular Drugs ◆ 53 Blockage of beta-2 adrenergic receptors in the lungs can produce bronchoconstriction (adrenaline is blocked); therefore, patients with chronic obstructive pulmonary disease (COPD) should not be given beta-2 blockers. If a COPD patient must use a beta blocker, a beta-1–selective agent (e.g., Lopressor) should be employed. (Beta-1 receptors are not present in the lungs. They are found in the heart and the kidneys.)

OTHER AGENTS Central-Acting Alpha-Adrenergic Inhibitors Central-acting alpha-adrenergic inhibiting agents (e.g., Catapres, Aldomet) act within the brainstem to suppress sympathetic outflow to the heart and blood vessels. 1. By suppressing sympathetic vasoconstriction of the blood vessels, these drugs promote vasodilation, bradycardia, and reduced cardiac output. 2. Blood pressure is reduced in both the supine and standing positions, unlike the peripheral alpha-adrenergic blockers, which tend to decrease blood pressure only when the patient is standing. 3. Central-acting alpha-adrenergic inhibiting agents are presented in Chapter 2.

Calcium Channel Blockers These reduce blood pressure by causing vasodilation of peripheral arterioles, arteries, and arterioles of the heart. Calcium channel blockers are presented in this chapter.

Angiotensin-Converting Enzyme Inhibitors These are the most frequently used drugs for controlling hypertension.

Selective Vasodilators The selective vasodilators include Apresoline, Loniten, and Nipride. Diazoxide (Hyperstat IV) reduces blood pressure by dilation of arterioles. Venous and arteriolar dilators (e.g., Nipride) reduce blood pressure by dilation of venous and arteriolar vessels. Selective vasodilators are presented in this chapter.

Adrenergic Neuron Blockers The adrenergic neuron blockers (e.g., Reserpine, Ismelin) reduce blood pressure by reducing the release of norepinephrine from sympathetic neurons. They act presynaptically. Adrenergic neuron blockers are presented in Chapter 2. Note: By activating beta-1 receptors, epinephrine increases cardiac output, thereby helping to elevate blood pressure. Blood pressure is also increased because of epinephrine’s ability to activate alpha-1 receptors in the peripheral vascular system, causing vasoconstriction. By activating beta-2 receptors in the lungs epinephrine can counteract bronchoconstriction. Norepinephrine can activate alpha-1 receptors in the peripheral vascular system, causing vascular constriction, and beta-1 receptors in the heart, increasing cardiac output. Dopamine receptor activation is discussed in Chapter 2.

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DRUG THERAPY FOR CARDIAC DYSRHYTHMIAS You have already studied the drugs used to treat cardiac dysrhythmias in this handbook. The drug classification listed here is to help you know the therapeutic regimens used to treat cardiac dysrhythmias. 1. 2. 3. 4. 5.

Sodium channel blockers (e.g., quinidine, lidocaine) are presented in this chapter. Calcium channel blockers (e.g., Calan, Isoptin) are presented in this chapter. Beta-adrenergic blockers (e.g., Lopressor, Inderal) are presented in Chapter 2. Muscarinic anticholinergic drugs (e.g., atropine) are presented in Chapter 2. Miscellaneous drugs (e.g., adenosine) are presented in this chapter.

◆ Miscellaneous Drugs for Dysrhythmias Generic Name

Trade Name

Adenosine Treatment of: Desired effect: Side effects: Nursing implications: Amiodarone HCl Treatment of:

• Adenocard Paroxysmal supraventricular tachycardia (PSVT)1 Normal sinus rhythm in patients diagnosed with PSVT Atrial tachydysrhythmia, hypotension, dyspnea, dizziness Adenosine slows conduction through the A-V node. Cordarone, Pacerone Use only for treatment of the following documented life-threatening recurrent ventricular arrhythmias that do not respond to other interventions or when alternative agents are not tolerated: recurrent ventricular fibrillation, recurrent hemodynamically unstable ventricular tachycardia; serious and even fatal toxicity has been reported with this drug; use alternative agents first; monitor patients receiving this drug very closely. Type III antiarrhythmic that acts directly on the cardiac cell membrane; prolongs repolarization and the refractory period; increases the ventricular fibrillation threshold; acts on peripheral smooth muscle cells to decrease peripheral resistance

Desired effect:

1 An apical pulse must be taken before administering adenosine. This drug is contraindicated in second- and third-degree heart

block.

DRUG THERAPY FOR MYOCARDIAL INFARCTION Thrombolytic agents and anticoagulants used to treat myocardial infarction (MI) are presented in Chapter 6. The drug classification listed here is to help you know the therapeutic regimen used to treat an MI. 1. Morphine is given to reduce pain and thereby reduce the release of catecholamines, which decreases cardiac workload, and is presented in Chapter 3.

Cardiovascular Drugs ◆ 55 2. Thrombolytic agents (e.g., streptokinase, urokinase) are presented in Chapter 6. 3. Anticoagulants (e.g., heparin, Coumadin, aspirin) are presented in Chapter 6.

DRUG THERAPY FOR HEART FAILURE You have already studied the drugs used to treat heart failure in this handbook. The drug classification listed here is to help you know the therapeutic regimens used to treat heart failure. 1. High-ceiling (loop) diuretics (e.g., Lasix, Edecrin) are presented in Chapter 4. 2. Potassium-sparing diuretics (e.g., Aldactone, Dyrenium) are presented in Chapter 4. 3. Cardiac glycosides (e.g., digoxin) are presented in detail in Chapter 2. 4. Beta-adrenergic agents (e.g., dopamine, dobutamine) are presented in Chapter 2.

DRUG THERAPY FOR ANGINA PECTORIS You have already studied the drugs used to treat angina pectoris in this handbook. The drug classification listed here is to help you know the therapeutic regimens used to treat angina pectoris. 1. Organic nitrates are the oldest and most frequently used antianginal drugs. These agents relieve angina by causing vasodilation of veins and arteries, decreasing preload and afterload. Nitroglycerin is the most frequently used organic nitrate. 2. Calcium channel blockers decrease the pain primarily by dilating arterioles, thus reducing the amount of blood returning to the ventricles; this reduces the workload of the heart and thus reduces cardiac oxygen demand, thereby relieving pain. a. Classic angina is triggered by an increase in activity, emotional excitement, large meals, and exposure to cold. The underlying cause is coronary artery disease (deposits of plaque in the coronary arteries). b. In variant angina, also called vasospastic angina, the patient experiences pain at rest due to coronary artery vasospasm. c. Unstable angina due to coronary artery vasospasm occurs when the patient is at rest, with symptoms gradually occurring more frequently and lasting longer. Unstable angina does not respond well to medications such as calcium blockers, nitroglycerin, or beta blockers. d. Nitroglycerin redistributes blood flow to ischemic myocardial areas, and improves perfusion without an increase in coronary blood flow. The principal adverse effects of nitroglycerin are headache, hypotension, and tachycardia.

Chapter

6

Drugs that Affect the Blood

The drugs discussed in this section are used to prevent formation of thrombi (intravascular blood clots) and to remove thrombi that have already formed. These drugs act in several ways: some suppress coagulation, some inhibit platelet aggregation, and some promote clot dissolution. All of these drugs interfere with normal hemostasis; therefore, they carry a significant risk of hemorrhage.

◆ Oral Anticoagulant Generic Name

Trade Name

Warfarin Desired effects:

Coumadin Interferes with the hepatic synthesis of vitamin K–dependent clotting factors (factors II, VII, IX, and X, and prothrombin), resulting in their eventual depletion and prolongation of clotting time. Coumadin is used to prevent thrombosis; in contrast to heparin, Coumadin has a delayed onset of action, which makes it inappropriate for emergency use; it is employed most frequently for long-term prophylaxis of thrombosis; initial response to Coumadin may not be evident until 8–12 hours after administration; its peak effects do not develop for several days; therefore, the physician will start the patient on Coumadin 2–3 days prior to discontinuing the heparin.

Treatment:

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Drugs that Affect the Blood

◆ 57

ASPIRIN Antiplatelet therapy with aspirin has three applications: (1) prevention of acute myocardial infarction (MI) in clients with unstable angina, (2) prevention of reinfarction in clients who have experienced an acute MI, and (3) prevention of stroke in clients with a history of transient ischemic attacks (TIAs). Other classifications for aspirin include analgesic, antirheumatic, salicylate, and nonsteroidal anti-inflammatory drug (NSAID).

◆ Vitamin K Antagonist Generic Name

Trade Name

Warfarin Desired effects:

Coumadin Coumadin interferes with the hepatic synthesis of vitamin K, resulting in prolongation of clotting time; vitamin K is also an antiplatelet drug, and therefore inhibits clotting. Used to prevent vascular thrombosis Bleeding is the major complication. After Coumadin is discontinued; coagulation remains inhibited for 2–5 days; this residual effect is due to its long half-life. The anticoagulant effects of Coumadin are evaluated by monitoring prothrombin time (PT), a coagulation test; the average normal PT is 11–12.5 seconds; treatment with Coumadin prolongs the PT. The effects of Coumadin overdose can be overcome with vitamin K, (AquaMEPHYTON); vitamin K is an antagonist of Coumadin and will reverse Coumadin-induced inhibition of clotting factor synthesis.

Treatment: Side effects: Nursing implications: Monitoring:

Antidote:

◆ Antiplatelet Drugs Generic Name

Trade Name (Route)

Aspirin Dipyridamole Abciximab Cilostazol Clopidogrel Sulfinpyrazone Ticlopidine

Bayer, Ecotrin (PO) Persantine, Dipridacot (PO, IV) [Canada] ReoPro (IV) Pletal (PO) Plavix (PO) Anturane (PO) [Canada] Ticlid (PO) • Aspirin Higher doses of aspirin inhibit the synthesis of prostacyclin, a potent vasodilator and inhibitor of platelet aggregation; analgesic and anti-inflammatory effects are attributed to aspirin’s ability to inhibit the synthesis of prostaglandin.

Desired effects:

(continued)

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◆ Chapter 6

◆ Antiplatelet Drugs (continued) Generic Name

Trade Name (Route)

rAspirin (continued) Side effects:

Treatment:

Nursing implications:

Desired effects:

Side effects: Nursing implications:

Treatment:

Desired effects: Side effects: Treatment of:

Nursing implications:

Desired effects:

Thrombocytopenia, agranulocytosis, leukopenia, neutropenia, hemolytic anemia, increased prothrombin time, nausea, vomiting, GI bleeding, diarrhea, heartburn, anorexia, hepatitis, Reye’s syndrome seizures Used for moderate pain or fever including rheumatoid arthritis, osteoarthritis, thromboembolic disorders, transient ischemic attacks, rheumatic fever, post–myocardial infarction, prophylaxis of MI, ischemic stroke, angina Liver function studies (AST, ALT); bilirubin if patient is on long-term therapy; renal function studies; BUN; urine creatinine if patient is on long-term therapy rDipyridamole Decreases coronary vascular resistance and increases coronary blood flow without increasing myocardial oxygen consumption; inhibits platelet aggregation; interferes with platelet membrane function by inhibiting fibrinogen binding and platelet-platelet interactions; prolongs bleeding time MI, ventricular fibrillation (IV); respiratory: bronchospasm (IV); GU: possible decreased fertility and loss of eggs in women Provide continual monitoring of ECG, BP, and orientation during administration of IV dipyridamole; administer oral drug at least 1 hour before meals with a full glass of fluid PO: persantine is used to prevent thromboembolism in patients with prosthetic heart valves; IV: diagnostic aid in evaluation of coronary artery disease (CAD) in patients who cannot exercise, and as an alternative to exercise in thallium myocardial perfusion imaging studies; unlabeled uses: prevention of MI or reduction of mortality post-MI; with aspirin to prevent coronary bypass graft occlusion rAbciximab Antithrombotic monoclonal antibody; antiplatelet agent for percutaneous coronary interventions (PCI) and acute arterial occlusive disorders Thrombocytopenia, bleeding, bradycardia, hypotension, arrhythmias, pneumonia, pleural effusion ReoPro is used in combination with percutaneous transluminal coronary angioplasty or atherectomy for the prevention of acute cardiac ischemic complications in patients at high risk for abrupt closure of the treated coronary vessel; it is intended to be used with heparin and aspirin therapy; early treatment of unstable angina and non-ST–segment elevation MI Monitor CBC and liver and renal function tests; history: allergy to abciximab, neutropenia, thrombocytopenia, hemostatic disorders, bleeding ulcer, intracranial bleeding, severe liver disease, lactation, renal disorders, pregnancy, recent trauma rCilostazol Inhibits platelet aggregation induced by a variety of stimuli, including ADP, thrombin, collagen, shear stress, epinephrine, and arachidonic acid by inhibiting cAMP phosphodiesterase III (PDE III); produces vascular dilation in vascular beds with specificity for femoral beds; seems to have no effect on renal arteries

Drugs that Affect the Blood

◆ 59

◆ Antiplatelet Drugs (continued) Generic Name

Trade Name (Route)

rCilostazol (continued) Side effects: Treatment: Nursing implications:

Desired effects: Side effects: Treatment:

Nursing implications:

Desired effects:

Side effects: Treatment: Nursing implications:

Drug classification: Nursing implications:

Dizziness, headache, tachycardia, peripheral edema, infection and back pain Reduction of symptoms of intermittent claudication, allowing increased walking distance Monitor blood clotting studies prior to and periodically during therapy; administer drug on an empty stomach ≥30 minutes before or 2 hours after breakfast and dinner; advise patients to use barrier contraceptives while receiving this drug, as it may harm the fetus. rClopidogrel Inhibits platelet aggregation by blocking receptors on platelets, preventing clumping of platelets Hypertension, edema, nausea, GI distress, constipation, diarrhea, GI bleeding, increased bleeding risk Treatment of patients at risk for ischemic events, including history of MI, ischemic stroke, and peripheral artery disease; treatment of patients with acute coronary syndrome Use cautiously with bleeding disorders, recent surgery, closed head injury, or pregnancy; potential increased risk of GI bleeding with NSAIDs, so monitor patient carefully; potential increased bleeding with warfarin, so monitor carefully; history: allergy to clopidogrel, pregnancy, lactation, bleeding disorders, recent surgery, closed head injury rSulfinpyrazone Inhibits the renal tubular reabsorption of uric acid, increasing the urinary excretion of uric acid, decreasing serum uric acid levels, retarding urate deposition, and promoting the resorption of urate deposits; inhibits prostaglandin synthesis, which prevents platelet aggregation, but lacks analgesic and anti-inflammatory activity Exacerbation of gout and uric acid stones, renal failure, hematologic disorders, blood dyscrasias, nausea, vomiting, diarrhea Inhibits platelet aggregation Report flank pain, dark urine or blood in the urine, acute gout attack, unusual fatigue or lethargy, and unusual bleeding or bruising; take the drug with meals or antacids to prevent GI upset; to prevent side effects (exacerbation of a gouty attack or renal stones), drink plenty of fluids, 2.5–3 L/day; also take with meals and use antacids; avoid the use of aspirin and aspirin-containing products; serious toxic effects could occur. These include antiplatelet agent, antigout agent, and uricosuric agent. Administer drug with meals to prevent GI upset; encourage patients to drink 2–3 liters of fluids per day to decrease the risk of renal stone development; check urine alkalinity (urates crystallize in acid urine); use sodium bicarbonate or potassium citrate to alkalinize urine (continued)

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◆ Chapter 6

◆ Antiplatelet Drugs (continued) Generic Name Desired effects:

Side effects: Treatment: Nursing implications:

Trade Name (Route)

rTiclopidine Interferes with platelet membrane function by inhibiting fibrinogen binding and platelet interactions; inhibits platelet aggregation and prolongs bleeding time; the effect is irreversible for life of the platelets. Hematologic: neutropenia, thrombotic thrombocytopenic purpura, bleeding; local: pain, phlebitis, thrombosis at injection site Reduces risk of thrombotic stroke in patients who have experienced stroke Decreased effectiveness of digoxin; increased serum levels and effects of theophylline and aspirin; decreased absorption with antacids; take the drug with meals or just after eating; patients require regular blood tests to monitor response to this drug.

◆ Parenteral Anticoagulants Generic Name

Trade Name (Route)

Heparin Dalteparin sodium Enoxaparin sodium Tinzaparin sodium Desired effects:

No commonly used trade name (IV, SC) Fragmin (SC) Lovenox (SC) Innohep (SC) • Heparin: Inactivates factor Xa, thereby inhibiting thrombus and clot formation by blocking the conversion of prothrombin and fibrinogen to fibrin, the final step in the clotting process; heparin also inhibits the activation of factor XIII. • Fragmin, Lovenox, Innohep: Produces anticoagulation by inhibition of factors Xa and IIa, preventing the formation of clots These anticoagulants are used to prevent vascular thrombosis, which may lead to pulmonary thrombosis; prophylaxis for hip and abdominal surgery Monitor WBC count before use and frequently while initiating therapy; if neutropenia is present or occurs, discontinue drug immediately; monitor for any signs of excessive bleeding (e.g., bruises, dark stools); for heparin, monitor activated partial thromboplastin time (aPTT)

Treatment: Nursing implications:

Note: Heparin is prescribed in units, not in milligrams. Warning: Keep protamine sulfate (1% solution) readily available in case of overdose.

THROMBOLYTIC DRUGS As their name implies, the thrombolytic drugs act to remove thrombi that have already formed. This is in contrast with the anticoagulants, which act to prevent thrombus formation.

Drugs that Affect the Blood ◆ 61

◆ Thrombolytic Drugs Generic Name

Trade Name

Alteplase Streptokinase Reteplase Urokinase Desired effect: Side effects: Treatment:

Activase (tissue plasminogen activator [t-PA]) No commonly used trade name Retavase No commonly used trade name Destroy pre-existing blood clots Bleeding is the major complication. Thrombolytic drugs have three major indications: (1) acute coronary thrombosis (acute myocardial infarction), (2) massive pulmonary emboli, and (3) deep vein thrombosis; in all three situations, timely intervention is essential; for example, for treatment of coronary thrombosis (MI), best results are obtained when thrombolytic therapy is started within 4–6 hours of the diagnosis Regularly monitor coagulation studies; apply pressure or pressure dressings to control bleeding (at invaded or disturbed areas); avoid any arterial invasive procedures; arrange for typing and cross-matching of blood if serious blood loss occurs and whole blood transfusions are required; thrombolytic drugs can only be given by the IV route. Several measures can reduce the risk of bleeding while a client is using thrombolytic agents; these include: (1) avoiding subcutaneous and intramuscular injections, (2) minimizing physical manipulation of the client, (3) minimizing invasive procedures, (4) avoiding (whenever possible) concurrent use of anticoagulants (e.g., heparin, Coumadin) and avoiding concurrent use of antiplatelet drugs (e.g., aspirin). Because of the risk of bleeding, thrombolytic drugs are absolutely contraindicated for patients with active internal bleeding disorders; other contraindications include recent thoracic or abdominal surgery, recent serious trauma, and recent history of GI bleeding, organ biopsy, and lumbar puncture.

Nursing implications:

◆ Calcium Regulator Drugs Generic Name

Trade Name

Alendronate Etidronate Calcitonin

Fosamax Didronel Calcitonin (human), calcitonin (salmon) • Fosamax Slows normal and abnormal bone resorption without inhibiting bone formation and mineralization

Desired effects:

(continued)

◆ Calcium Regulator Drugs (continued) Generic Name

Side effects: Treatment: Nursing considerations:

Desired effects: Side effects: Treatment:

Nursing implications:

Desired effects:

Side effects: Treatment:

Nursing implications:

Trade Name • Fosamax (continued) Headache, nausea, bone pain Osteoporosis in postmenopausal women and men with osteoporosis; treatment of glucocorticoid-induced osteoporosis Take the drug in the morning with a full glass of plain water (not mineral water), at least 30 minutes before any beverage, food, or medication and stay upright for 30 minutes. • Didronel Slows normal and abnormal bone resorption; reduces bone formation and bone turnover Hematological: elevated BUN and serum creatinine; increased or recurrent bone pain, focal osteomalacia Paget’s disease of bone (oral), heterotopic ossification (oral), hypercalcemia of malignancy in patients inadequately managed by diet or oral hydration (parenteral); unlabeled use: treatment of postmenopausal osteoporosis and prevention of early menopausal bone loss Administer with a full glass of water 2 hours before patient takes their medication; monitor serum calcium levels before during and after therapy. Ensure a 3-month rest period after treatment for Paget’s disease if retreatment is required, and 7 days between treatments for hypercalcemia of malignancy; ensure adequate vitamin days and calcium intake; provide comfort measures if bone pain returns. • Calcitonin The calcitonins are polypeptide hormones secreted by the thyroid; human calcitonin is a synthetic product classified as an orphan drug; salmon calcitonin appears to be a chemically identical polypeptide but with greater potency per milligram and longer duration; inhibits bone resorption; lowers elevated serum calcium in children and excretion of filtered phosphate, calcium, and sodium by the kidney Flushing of face, hand rash, nausea, vomiting, increased urinary frequency Human and salmon calcitonin are used in the treatment of Paget’s disease; salmon calcitonin is used in the treatment of postmenopausal osteoporosis in conjunction with adequate calcium and vitamin D intake to prevent loss of bone mass; salmon calcitonin is used in the treatment of hypercalcemia as emergency treatment. Assess for allergy to salmon calcitonin or fish products; inject doses of more than 2 mL IM, not SC; use multiple injection sites; refrigerate nasal spray until activated, then store at room temperature.

Note: Didronel can be administered IV or PO.

Use calcitonin cautiously with renal insufficiency, osteoporosis, and pernicious anemia. Also, keep parenteral calcium on hand in case of the development of hypocalcemic tetany.

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Drugs that Affect the Blood

◆ 63

DEFICIENCY ANEMIA 1. Anemia is defined as a decrease in erythrocyte number, size, or hemoglobin content. 2. Causes of anemia include blood loss, hemolysis, bone marrow dysfunction, and deficiencies of substances essential for hematopoiesis (red blood cell formation and maturation). 3. Most deficiency anemias result from a deficiency in vitamin B12 , iron, or folic acid. 4. Iron-deficiency anemia is much more common than anemia due to deficiency of vitamin B12 or folic acid.

◆ Drugs for Deficiency Anemia Generic Name

Trade Name

Epoetin alfa Treatment:

Epogen, Procrit Erythropoietin is one endogenous factor controlling the rate of cell production; a synthetic drug, epoetin alfa has been developed using recombinant DNA technology; epoetin alfa is used to treat anemia caused by reduction of endogenous erythropoietin production; causes include end-stage renal disease, anemia caused by zidovudine, and anemia caused by chemotherapy Seizures, hypertension, hypertensive encephalopathy

Side effects:

IRON-DEFICIENCY ANEMIA 1. Groups considered most frequently at risk for developing iron-deficiency anemia are infants under 2 years of age, teenagers, pregnant women, and the very elderly. Pregnant teenagers are frequently at very high risk. 2. Iron deficiency manifests ultimately by the development of anemia, which is corrected by giving diets rich in absorbable iron and by providing iron supplements in the form of ferrous sulfate or ferrous gluconate. 3. Iron deficiency can be caused by (1) chronic blood loss, such as a bleeding peptic ulcer, hemorrhoids, parasites, or malignancy; (2) faulty iron absorption, iron-poor diet, or chronic GI disturbances such as diarrhea; and (3) increased iron requirement that occurs in expanded blood volume as seen in infancy, adolescence, and pregnancy.

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Nursing Implications 1. Liquid iron preparations can stain teeth. The effect can be prevented by diluting liquid preparation with juice or water, administering the iron through a straw or with a dropper, and rinsing the mouth after administration. 2. In addition to medication, attention should be given to the amount of absorbable iron in foods. Liver, kidney, egg yolk, dried fruit, beans, nuts, raisins, green leafy vegetables, and fortified cereals rank highest in iron content. 3. Oral ferrous sulfate is the drug of choice for treating iron-deficiency anemia. Iron is best absorbed when the stomach is empty; however, under these conditions it tends to cause gastric irritation. 4. Sustained-release or enteric-coated iron preparations reduce gastrointestinal side effects by preventing rapid dissolution of iron; at the same time, however, they may allow iron to bypass the jejunum, which is the most active site of iron absorption. 5. Side effects are dose-related, and smaller dosages have been suggested with the expectation that the therapeutic program will be longer. 6. If the patient is not taking the oral iron supplement because of the side effects of the iron or it is not being absorbed (possibly as a result of malabsorption), then iron dextran may be administered parenterally (IM). 7. Clinical findings of iron-deficiency anemia are reflected in a variety of symptoms, including fatigue, anorexia, and pica, especially pagophagia (eating ice).

PERNICIOUS ANEMIA 1. The cause of pernicious anemia (also known as megaloblastic anemia) is a deficiency of vitamin B12 . 2. Insufficient vitamin B12 in the diet is rarely a cause of deficiency. Potential causes for poor absorption include regional enteritis and celiac disease (a malabsorption syndrome involving abnormalities in the intestinal villi). 3. Most frequently, the cause of pernicious anemia is impaired absorption of vitamin B12 secondary to lack of intrinsic factor. The principal causes of intrinsic factor deficiency are atrophy of gastric parietal cells and surgery of the stomach (partial or total gastrectomy). 4. It is important to note that hematologic effects of vitamin B12 deficiency can be reversed with B12 given parenterally (IM). When folic acid is administered in large amounts, some of it can be activated independent of vitamin B12 and this will also reverse the hematologic effects of vitamin B12 deficiency. 5. Treatment of severe vitamin B12 deficiency involves the following: (1) IM injections of vitamin B12 and folic acid (the folic acid accelerates recovery of hematologic deficits), (2) administration of 2–3 units of packed red blood cells (to correct anemia quickly), (3) transfusion of platelets (to suppress bleeding), and (4) therapy with antibiotics if infection has developed.

Drugs that Affect the Blood

◆ 65

6. When megaloblastic anemia (oversized erythroblasts appear in bone marrow and in the blood) occurs, it may be due to vitamin B12 deficiency or lack of folic acid; therefore, a definitive diagnosis must be made before treatment. 7. Two tests are particularly helpful for establishing a diagnosis of vitamin B12 deficiency: measurement of plasma vitamin B12 content (it will be low if B12 is not being absorbed), and the Schilling test, which measures vitamin B12 absorption. 8. The Schilling test is performed by administering a small dose of radioactive vitamin B12 , after which the urine is monitored for the appearance of radioactivity. If the urine remains free of radioactivity, one can conclude that vitamin B12 was not absorbed and absorption is impaired. The combination of plasma vitamin B12 measurement and the evidence of vitamin B12 malabsorption permits a clear diagnosis of pernicious anemia and folic acid deficiency is ruled out.

Nursing Implications 1. Parenteral forms of cyanocobalamin can be administered by intramuscular or deep subcutaneous injection. 2. Parenteral administration is required for all patients who are able to absorb oral vitamin B12 . Patients unable to absorb vitamin B12 should be assessed for pernicious anemia, as described in the previous section. 3. Deficiency of vitamin B12 causes demyelination of neurons, primarily in the spinal cord and brain. 4. The neuronal injury produces paresthesias (tingling and numbness) of the hands and feet and a reduction in deep tendon reflexes. 5. Late-developing responses include loss of memory, mood changes, hallucinations, and psychosis. 6. If vitamin B12 deficiency is prolonged, neurologic damage can become permanent. 7. Vitamin B12 deficiency also prevents the bone marrow from forming leukocytes (white blood cells) and thrombocytes (platelets). Therefore, assessment for infection and bleeding is a priority for patients with pernicious anemia. 8. Anemia may cause peripheral and cerebral hypoxia. Heart failure and dysrhythmias are the most frequent causes of death.

FOLIC ACID DEFICIENCY 1. Folic acid deficiency also causes megaloblastic anemia. Folic acid is necessary for DNA synthesis; without folic acid, DNA replication and cell division become disrupted. 2. In order to be usable, folic acid must be converted by vitamin B12 to an active form. As discussed before, however, when large amounts of folic acid (also known as folate) are ingested, some of this folic acid can be activated via an alternative pathway—one that does not employ vitamin B12 . Hence, even in the absence of

66

◆ Chapter 6 vitamin B12 , if sufficient amounts of folic acid are consumed, active folate will be available for DNA synthesis. 3. In contrast to vitamin B12 , folic acid is not rigidly conserved; significant amounts are excreted every day. If the intake of folic acid was to significantly decrease within a few weeks (if body stores were already low), severe folic acid deficiency would occur.

Nursing Implications 1. Folic acid deficiency has two principal causes: (1) low consumption of folic acid (especially as seen in alcoholics), and (2) malabsorption secondary to intestinal disease. 2. The modality of treating folic acid deficiency should match the cause. If folic acid deficiency is due to poor diet, the deficiency is corrected by dietary measures and not by drugs. 3. Ingesting one fresh vegetable or one glass of fruit juice a day will usually correct the deficiency. 4. In contrast, when folate deficiency is the result of malabsorption, diet alone will not correct the deficiency, and a pharmaceutical preparation of folate is needed.

ANTILIPEMIC AGENTS The antilipemics are used to lower blood cholesterol.

◆ HMG-CoA Reductase Inhibitors (Statins) Generic Name

Trade Name

Atorvastatin Fluvastatin Simvastatin Lovastatin Rosuvastatin calcium Pravastatin Desired effects:

Lipitor Lescol Zocor Mevacor Crestor Pravachol HMG-CoA reductase inhibitors inhibit the enzyme that catalyzes the first step in the cholesterol synthesis pathway, resulting in a decrease in serum cholesterol, serum LDL (which is associated with an increased risk of coronary artery disease), and either an increase or no change in serum HDL (which is associated with a decreased risk of coronary artery disease).

Drugs that Affect the Blood

◆ 67

◆ HMG-CoA Reductase Inhibitors (Statins) (continued) Generic Name

Trade Name

Pravastatin (continued) Side effects:

Pravachol Headaches, blurred vision, dizziness, insomnia, flatulence, abdominal pain, constipation, cataracts, and elevations of CPK and alkaline phosphatase Adjuncts to dietary modification in the treatment of elevated total cholesterol and LDL in patients with primary hypercholesterolemia whose response to dietary restriction of saturated fat and cholesterol and other pharmacologic measures has not been adequate: primary prevention of coronary events (Lovastatin, Pravastin); secondary prevention of CV events (Fluvastatin, Lovastatin, Simvastatin) Administer the drug at night; highest rates of cholesterol synthesis occur between midnight and 5 A.M.; consult with a dietitian about low-cholesterol diets; arrange for diet and exercise consultation; arrange for periodic ophthalmologic examinations to check for cataract development

Treatment:

Nursing implications:

◆ Bile-Acid Binding Sequestrants Generic Name

Trade Name

Cholestyramine Colestipol Colesevelam Desired effects:

Cholybar, Questran Colestid Welchol They bind bile acids in the intestine to form a complex that is excreted in the feces; as a result cholesterol is lost, oxidized in the liver, and serum cholesterol and LDL are lowered. Hematuria, dysuria, diuresis, constipation due to fecal impaction, exacerbation of hemorrhoids, increased bleeding tendencies related to vitamin K malabsorption deficiencies; decreased absorption of fat-soluble vitamins; decreased serum levels or delayed absorption of thiazide diuretics and digitalis; decreased absorption of other oral drugs; administer them 1 hour before or 4–6 hours after colestipol. Adjunct therapy: reduction of elevated serum cholesterol in patients with primary hypercholesterolemia (elevated LDL) Do not administer drug in dry form; mix in food (e.g., soup or cereal) and add the prescribed 90 mL of liquid; stir until completely mixed; make sure that patients swallow tablets whole; do not cut, crush, or chew them; tablets should be taken with plenty of fluids

Side effects:

Treatment: Nursing implications:

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◆ Chapter 6

◆ Fibric Acid Derivatives (Fibrates) Generic Name

Trade Name

Fenofibrate Gemfibrozil Desired effects:

Tricor Lopid Fibrates break down the particles that make up triglycerides; these drugs are usually taken twice a day: 30 minutes before breakfast and before the evening meal. Cardiac arrhythmias, angina, phlebitis, thrombophlebitis, rash, impotence, decreased libido, flulike symptoms, myalgia, gastrointestinal discomfort, aching muscles, sensitivity to sun, skin rashes Adjuncts to diet in treating adults with primary hypercholesterolemia and hypertriglyceridemia Advise patients to take these drugs with meals; continue to follow a strict dietary regimen and exercise program; arrange to have regular follow-up visits with the health care provider, which will include blood tests.

Side effects:

Treatment: Nursing implications:

◆ Cholesterol Absorption Inhibitor Generic Name

Trade Name

Ezetimibe Desired effects:

Zetia This cholesterol absorption inhibitor hinders the absorption of cholesterol by the small intestine; this leads to decreased delivery of dietary cholesterol to the liver, which will increase the clearance of cholesterol from the blood and lead to a decrease in serum cholesterol. Headache, dizziness, fatigue, abdominal pain, myalgia, viral infection, back pain Zetia is used as an adjunct to diet and exercise to lower cholesterol, LDL, and Apo-B levels in patients with primary hypercholesterolemia as monotherapy or in combination with an HMG-CoA reductase inhibitor (statin); used in combination with atorvastatin or simvastatin for the treatment of homozygous familial hypercholesterolemia as an adjunct to other lipid-lowering therapy Monitor serum cholesterol, LDL, and triglycerides before starting treatment and periodically during treatment; determine that the patient has been on a low-cholesterol diet and exercise program for at least 2 weeks before starting Zetia; help nursing mothers to find another method of feeding their babies if this drug must be taken; it is not known if the drug enters breast milk.

Side effects: Treatment:

Nursing implications:

Drugs that Affect the Blood

◆ 69

GENERAL GUIDELINES FOR DRUG TREATMENT 1. Expert guidelines now recommend starting cholesterol-lowering drugs along with a diet and exercise regimen for the following groups: a. People with LDL levels of 130 mg/dL or greater if they have existing heart disease or risk factors that place them in equivalent danger. Such factors include diabetes or other disease that suggests atherosclerosis (such as peripheral artery disease or blockage in the carotid artery). Their goal is to achieve an LDL level of 100 mg/dL. b. People with LDL cholesterol levels of 160 mg/dL or greater who have no existing heart disease but have two or more risk factors. Their goal is an LDL level of 130 mg/dL. c. People whose LDL is 190 mg/dL or over who have one or no risk factors. They should strive for LDL levels of 160 mg/dL or less. 2. Evidence now strongly suggests that cholesterol-lowering drugs are improving survival in heart attack patients. Experts now recommend that drug treatment be tailored to raise or lower specific lipids, depending on the patient’s blood lipid levels. 3. The body needs cholesterol for digesting dietary fats, making hormones, building cell walls, and other important processes, but too much circulating cholesterol can injure arteries, especially the coronary arteries. This leads to accumulation of cholesterol-laden plaque on vessel walls, a condition called atherosclerosis. 4. It is true that lowering cholesterol can benefit the heart. Cholesterol is critically important for every cell in the body, and lowering it too much may damage other organs, according to Dr. Beatrice Golomb, a cholesterol researcher at the University of California, San Diego. Dr. Golomb and other researchers are especially concerned about the brain, which makes up less than 4% of the body’s weight but contains 25% of its cholesterol. Dr. Golomb states that “Brain cells require cholesterol to communicate with each other.” This may explain why studies at the University of Pittsburgh and elsewhere have shown that people who take cholesterol-lowering drugs have poorer memories and slower motor reflexes, and why men in earlier cholesterol-lowering studies had fewer heart attacks but more fatal car accidents.

Chapter

7

Endocrine Drugs

DRUG THERAPY FOR TYPE II (NON-INSULIN-DEPENDENT) DIABETES MELLITUS 1. Non-insulin-dependent diabetes mellitus (NIDDM) is the most prevalent type of diabetes. Approximately 10 million Americans are known to have this disease. 2. NIDDM has two alternative names: type II diabetes mellitus and adult-onset diabetes mellitus. 3. Patients with NIDDM can take oral hypoglycemic agents because some of the beta cells (insulin-producing cells of the pancreas) can still produce insulin when stimulated with these drugs.

DRUG THERAPY FOR TYPE I (INSULIN-DEPENDENT) DIABETES MELLITUS 1. Insulin-dependent diabetes mellitus (IDDM) accounts for about 10% of all diabetes. Approximately 1 million Americans have this disorder. 2. IDDM is known by three alternative names: type I diabetes mellitus, juvenileonset diabetes mellitus, and ketosis-prone diabetes mellitus. As a rule, IDDM 70

Endocrine Drugs ◆ 71 develops during childhood or adolescence. Onset of symptoms is usually abrupt. 3. The primary defect in IDDM is destruction of pancreatic beta cells (the cells responsible for insulin synthesis). When insulin is not available to carry sugar into the cells, the body will then burn fat, producing ketones and acids. The client is in a state of hyperglycemia and may go into a state of ketoacidosis.

◆ Oral Medications for Type II Diabetes Generic Name

Trade Name (When to Take)

Drug classification Antidiabetic Sulfonylureas Glyburide Glipizide Glimepiride Tolbutamide Chlorpropamide Acetohexamide Drug classification Antidiabetic, Meglitinide Repaglinide Nateglinide Drug classification Antidiabetic Metformin Metformin Drug classification Antidiabetic

Mechanism of action: Stimulate insulin release Micronase, DiaBeta (with meals) Glucotrol (30 minutes before meals) Amaryl (with breakfast) Orinase (before breakfast) Diabinese (before breakfast) Dymelor (Canada), Dymelor (before morning and evening meals) Mechanism of action: Stimulate insulin release Prandin (15 minutes before each meal) Starlix (30 minutes before each meal)

Precose Glyset Drug classification Thiazolidinedione: Rosiglitazone Pioglitazone Clinical alert:

Desired effect: Side effects: Treatment:

Glucophage (with meals) Glucophage XL (with meals) Alpha-glucosidase inhibitors Mechanism of action: Limit carbohydrate absorption Acarbose (with first bite of a meal) Miglitol (with first bite of a meal) Mechanism of action: Increases insulin sensitivity at insulin receptor sites to lower blood glucose, decreases hepatic gluconeogenesis, and increases insulin dependent muscle glucose uptake. Avandia(with or without food) Actos (with or without food) Name confusion has occurred between DiaBeta (glyburide) and Zebeta (bisoprolol), so use caution; Zebeta is a beta-selective adrenergic blocking agent; assess the patient for signs and symptoms of hyperosmolar coma, which are polyuria, polyphagia, and severe dehydration. Control blood glucose in non-insulin-dependent diabetics Hypoglycemia Non-insulin-dependent type II diabetes mellitus (NIDDM)

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NURSING IMPLICATIONS FOR TYPE II DIABETES MELLITUS 1. Transfer to insulin therapy during periods of stress (e.g., infection, surgery, or trauma). 2. Consult with a dietitian to establish a weight loss program and dietary control as appropriate. 3. The diabetic teaching program should include details of the disease, dietary control, exercise, signs and symptoms of hypoglycemia and hyperglycemia, avoidance of infection, and good hygiene. 4. Provide good skin care to prevent breakdown. 5. Assess the patient for hyperosmolar nonketotic diabetic coma, as it is usually a complication in patients with NIDDM. It is a state of profound dehydration resulting from sustained hyperglycemia and diuresis if the client is unable to drink sufficient fluids to maintain proper fluid levels. Administer IV normal saline as prescribed by the physician. 6. When a patient with NIDDM is developing hyperosmolar hyperglycemic nonketotic syndrome the only apparent signs and symptoms are diuresis and dehydration. 7. When a patient with IDDM develops ketoacidosis, there will be many apparent signs and symptoms (e.g., nausea, vomiting, and Kussmaul’s breathing), which bring the patient to physician attention before extreme dehydration can occur. Such a protective mechanism is not present in type II diabetics. Note: The reason for the absence of ketoacidosis in type II diabetes is not known.

NURSING IMPLICATIONS FOR TYPE I DIABETES MELLITUS 1. The intent is to reduce blood glucose levels by facilitating metabolism of glucose and to prevent excessive breakdown of protein. 2. The main side effects are hypoglycemia and ketoacidosis. Symptoms of ketoacidosis include polyuria, polyphagia, dehydration, fruity breath, and Kussmaul’s breathing. 3. Treatment is with insulin administered SC with the needle at a 90-degree angle; no aspiration is necessary. Regular insulin is clear and long-lasting insulin is cloudy; the bottle of insulin must be rolled in the hands to mix well before administration. If regular and long-lasting insulin are to be administered in combination, the regular insulin is drawn into the syringe first. Use only an insulin syringe when administering insulin.

DIAGNOSIS OF TYPE I DIABETES MELLITUS 1. Glycosylated hemoglobin (A1c ) is a diagnostic test for blood glucose level over a period of 2–3 months. If the blood glucose level has not been

Endocrine Drugs ◆ 73

TABLE 7–1 ◆ Hypoglycemic Agents (IV and SC) Type of Insulin Rapid-acting Insulin Lispro (Humalog) Insulin Aspart (NovoLog) Short-acting Regular (Humulin R, Novolin R) Intermediate-acting NPH (Humulin N, Novolin N) Lente (Humulin L, Novolin L) Long-acting Ultralente (Humulin U) Insulin glargine (Lantus) Premixed insulins NPH/regular 70%/30% Novolin/regular 70%/30% NPH/regular 50%/50% Lispro/regular 75%/25% Ultralenta/regular 70%/30% Premixed insulin onset, peak and duration depends on type of insulin mixture

Time of Onset

Peak of Action

Duration of Action

Route and Appearance

5 min 5–10 min

0.5–1.5 1–3 h

3–4 h

Clear (SC and IV) Clear (SC and IV)

30–60 min

2–3 h

6–12 h

Clear (SC)

1–2 h 1–2 h

8–12 h 8–12 h

18–24 h 10–16 h

Cloudy (SC) Cloudy (SO)

4–8 h 60 min

10–30 h None

30–36 h 24 h

Cloudy (SC) Clear (SC) Cloudy (SC) Cloudy (SC) Cloudy (SC) Cloudy (SC) Cloudy (SC)

Notes: Humalog is faster-acting than Humulin R insulin. These two types of insulin have similar sounding names; therefore, care must be taken so the correct drug is administered. Insulin lispro (Humalog) and Insulin aspart (NovoLog) should not be used in an insulin infusion pump and cannot be mixed with other insulin products. Humalog is administered 15 minutes before meals and regular insulin is administered 30–60 minutes before meals. Regular insulin should not be mixed with zinc suspension insulin because of interference with its actions.

controlled in the preceding 2–3 months, the hemoglobin A1c level will be increased. 2. Home glucose monitoring involves obtaining a drop of capillary blood from a finger with a sterile lancet. The blood is placed on a semi-permeable membrane that contains a reagent. The amount of blood glucose in milligrams can be read with the use of a glucose meter (e.g., Acu-Chek, Glucometer). 3. Test urine for ketones (type I DM) when blood glucose levels are above 240 mg/ 100 mL in home care situations; in the hospital a blood test is used to detect ketones. 4. The fasting blood sugar test is used to diagnose diabetes mellitus. Two or more fasting blood glucose levels above 126 mg/100 mL are diagnostic of diabetes mellitus.

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HYPOGLYCEMIA, HYPERGLYCEMIA, AND KETOACIDOSIS 1. A hypoglycemic reaction occurs when (1) more insulin is administered than is needed for glucose metabolism; (2) the patient fails to eat the recommended number of calories; or (3) the patient exercises more than usual. 2. Hypoglycemic reactions usually occur during insulin peak time. The person may become nervous, trembling, confused, sweaty, weak, and irritable, and may complain of a headache with a blood sugar level <60 mg/dL. Giving sugar orally or glucose intravenously increases the utilization of insulin, and the symptoms usually disappear almost immediately. 3. Hyperglycemia occurs when the amount of insulin present is inadequate, and sugar cannot be metabolized and fat catabolism occurs. The use of fatty acids (ketones) for energy causes ketoacidosis (diabetic ketoacidosis that can lead to diabetic coma). 4. Signs and symptoms of hyperglycemia include polyuria, polydipsia, and polyphagia. Other symptoms may include blurred vision, fatigue, and dry mouth. To treat, regular insulin is given IV or SC. 5. Signs and symptoms of diabetic ketoacidosis include extreme thirst, polyuria, polydipsia, polyphagia, fruity breath odor, Kussmaul’s breathing (deep, rapid, labored breathing), rapid thready pulse, dry mucous membranes, poor skin turgor, and nausea and vomiting with a blood sugar level >400 mg/100 dL. If ketoacidosis is suspected, consult a physician immediately.

NURSING IMPLICATIONS FOR TYPE I DIABETES MELLITUS 1. Treatment of diabetics must be very individualized because patients respond differently when given the same amount and same kind of insulin. Some patients become hypoglycemic with a blood sugar of <70 mg/100 dL, but may not have symptoms of hypoglycemia. 2. The average normal blood glucose value according to the American Diabetes Association for adults is 70–120 mg/100 mL. 3. Thiazide diuretics, acute ingestion of alcohol, steroid preparations, thyroid preparations, estrogen, smoking, and rifampin may increase blood glucose, therefore increasing insulin requirements. 4. Anabolic steroids (e.g., testosterone), guanethidine, tricyclic antidepressants (e.g., Elavil) antidepressants (e.g., Prozac), MAOIs (e.g., Parnate), salicylates, phenylbutazone, and oral anticoagulants (e.g., Coumadin) may decrease insulin requirements. 5. Carefully assess the patient for symptoms indicative of insulin shock or diabetic acidosis. 6. Check glucose as ordered by a physician.

Endocrine Drugs ◆ 75 7. Administer insulin SC or oral hypoglycemic agents as ordered; know the time, peak, onset, and duration of action for each specific type of insulin you administer. 8. Explain dietary restrictions to the patient, in addition to the need for a steady, consistent level of exercise on a daily basis. 9. Patients with diabetes must understand the disease, its possible complications, and treatment. 10. Be certain that the patient understands the need for good hygiene and proper care of the feet. 11. Exercise may cause hypoglycemic reactions because sugar outside the cell is carried into the cell for energy production. 12. Stress may cause hyperglycemia because stress increases steroid and epinephrine production. Both of these increase glucose levels. 13. Assess the patient’s ability to understand dosage and administration of insulin SC or oral antidiabetic agents, as well as proper injection technique. 14. Explain the signs of insulin shock and diabetic ketoacidosis, and what to do if either of these conditions should develop.

DRUGS THAT MAY INCREASE BLOOD GLUCOSE LEVELS AND INSULIN REQUIREMENTS These may increase insulin requirements: glucagons, Bronkosol, Hyperstat, epinephrine, synthetic catecholamines, Alupent, Proventil, thiazide diuretics, Brethine, steroids, thyroid preparations, Ventolin, estrogen, rifampin, and Diuril. Consuming alcohol and smoking will also increase insulin requirements.

DRUGS THAT MAY DECREASE INSULIN REQUIREMENTS These may decrease insulin requirements: anabolic steroids (e.g., testosterone), tricyclic antidepressants (e.g., Elavil, Prozac), MAOIs (e.g., Parnate), salicylates, phenylbutazone, and anticoagulants (e.g., Coumadin).

DRUG THERAPY FOR THYROID DISORDERS 1. Thyroid hormones have profound effects on metabolism, cardiac function, growth, and development. These hormones stimulate the metabolic rate of most cells. 2. The thyroid gland produces two active hormones: triiodothyronine (T3 ) and thyroxine (T4 ). The preparations of T3 and T4 employed clinically are synthetic.

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◆ Agents Used to Treat Hypothyroidism (Myxedema) Generic Name

Trade Name

Liothyronine (T3 ) Levothyroxine (T4 ) Liotrix (T3 and T4 ) Desiccated thyroid

Cytomel Synthroid Thyrolar Armour Thyroid, S-P-T (this thyroid hormone preparation contains T3 and T4 in their natural state and ratio) Increases metabolic rate of body tissues, thereby increasing oxygen consumption, respiration, and heart rate; metabolism of fat, protein, and carbohydrate; and rates of growth and maturation Irritability, nervousness, insomnia, tachycardia, dysrhythmias, and weight loss Hypothyroidism, thyroid hormone replacement

Desired effects:

Side effects: Treatment:

Note: Synthroid interacts with many drugs (e.g., chloramphenicol, colestipol, norepinephrine, and anticoagulants).

NURSING IMPLICATIONS FOR HYPOTHYROIDISM 1. Provide a high-bulk diet and encourage activity to combat constipation and promote weight loss. 2. To prevent myxedema coma, tell the patient to continue the course of thyroid medication even if symptoms subside. 3. After thyroid replacement therapy begins, watch for symptoms of hyperthyroidism, such as restlessness, sweating, and excessive weight loss. 4. Check frequently for signs of decreasing cardiac output such as falling urine output.

AGENTS USED TO TREAT HYPERTHYROIDISM There are three major categories of thyroid inhibitors: thioamide derivatives (propylthiouracil, methimazole), iodides, and radioactive iodine. In addition to these agents, beta blockers (e.g., propranolol [Inderal]) can be used to treat hyperthyroid patients. Propranolol is used to decrease the symptoms of hyperthyroidism.

TREATMENT OF HYPERPARATHYROIDISM 1. A large volume of IV fluid is administered along with Lasix, forcing the excretion of sodium and calcium. 2. Calcitonin may be administered in life-threatening circumstances to decrease bone resorption of blood calcium; this will decrease serum calcium levels and increase deposition of calcium in bones, effects opposite of those of parathyroid hormone.

Endocrine Drugs ◆ 77

◆ Thioamide Derivatives Used for Hyperthyroidism (Graves’ Disease ) Generic Name

Trade Name

Methimazole Propylthiouracil Treatment:

Tapazole • Propyl-Thyracil (Canada), PTU PTU or Tapazole can be administered alone to control hyperthyroidism, employed as adjuncts to radiation therapy, or be given to suppress thyroid hormone synthesis in preparation for thyroid surgery (subtotal thyroidectomy) They suppress thyroid hormone synthesis; PTU or Tapazole do not destroy existing stores of the hormone; instead, they prevent thyroid hormone synthesis. Agranulocytosis: this reaction is rare and usually occurs during the first 2 months of therapy; agranulocytosis is an acute disease of the white blood cells in which the count drops to extremely low levels; hypothyroidism will occur with excessive dosing with PTU or Tapazole, which may cause the patient to enter a hypothyroid state; if this occurs, the dosage is reduced. PTU and Tapazole cross the placenta and can cause neonatal hypothyroidism and goiter; these drugs must be used judiciously during pregnancy to minimize effects on the fetus, and the dosage kept as low as possible; these drugs enter breast milk; therefore, a patient on PTU or Tapazole should be advised not to breast-feed.

Desired effect:

Side effects:

Nursing implications:

TREATMENT OF HYPOPARATHYROIDISM Because calcium absorption from the small intestine requires the presence of vitamin D, treatment includes vitamin D and calcium. Acute life-threatening tetany requires immediate IV administration of calcium gluconate or calcium chloride to raise serum calcium levels.

RADIOACTIVE IODINE (131 I) 1.

131

I, a radioactive isotope, is a stable form of iodine that emits a combination of beta particles and gamma rays. 131

I can be used to destroy thyroid tissue in patients with hyperthyroidism or cancer of the thyroid. The objective is to produce clinical remission without causing complete destruction of the gland. 3. The nurse must use gloves when handling urine containers and flush the toilet three times. 2.

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◆ Nonradioactive Iodide Products (Preoperative Medications) Generic Name

Trade Name

Strong iodine solution Potassium iodide Intravenous sodium iodide Treatment:

Lugol’s solution Potassium iodide solution (SSKI) No commonly used trade name

Side effects with nursing implications:

Lugol’s solution and SSKI are given to hyperthyroid individuals to suppress thyroid function in preparation for thyroid surgery; initial effects of SSKI or Lugol’s solution begin within the first 24 hours; peak effects develop in 10–15 days; in most cases, plasma levels of thyroid hormone are reduced with PTU prior to therapy with iodine; iodine solution (together with PTU) is then administered for the last 10 days prior to subtotal thyroidectomy Brassy taste, burning sensation in the mouth and throat, soreness of teeth and gums; sodium iodide (IV) is employed for acute management of thyrotoxic crisis, which may occur during or after surgery on the thyroid gland; benefits are derived from the ability of high concentrations of iodide to rapidly suppress thyroid hormone release; in treatment of thyrotoxicosis (a toxic condition due to hyperactivity of the thyroid gland), sodium iodide is used in combination with propylthiouracil and propranolol (Inderal); although sodium iodide rarely causes adverse side effects, severe hypersensitivity reactions have occurred; the most serious of these is edema of the larynx, and death can occur.

4. The advantages of 131 I treatment are: (1) low cost; (2) patients are spared the risk, discomfort, and expense of thyroid surgery; (3) death from 131 I treatment has never occurred; and (4) no tissue other than the thyroid is injured. 5. Disadvantages of 131 I treatment are that it takes several months to achieve maximum effect, and that treatment is associated with a significant incidence of delayed hypothyroidism. 6. Patients over age 30 may be candidates for 131 I therapy. 131 I is also indicated for those who have not responded to antithyroid drugs or to subtotal thyroidectomy. 7. Children are not considered good candidates because the rate of delayed hypothyroidism is higher in children than in adults. 131 8. I is contraindicated in pregnancy and lactation. Exposure of the fetus to 131 I after the first trimester may damage the immature thyroid, and exposure to radiation at any point in fetal life carries a risk of generalized developmental harm. 9. Since 131 I enters breast milk, women receiving this agent should not breastfeed.

Endocrine Drugs ◆ 79

PAGET’S DISEASE Paget’s disease is a slowly progressive metabolic bone disease characterized by an initial phase of excessive bone resorption (osteoclastic phase), followed by a reactive phase of excessive abnormal bone formation (osteoblastic phase). The new bone structure, which is fragile and weak, causes painful deformities of both external contour and internal structure. Paget’s disease usually localizes in one or several areas of the skeleton (most frequently the lower torso), but occasionally skeletal deformity is widely distributed. It can be fatal, particularly when it is associated with congestive heart failure (widespread disease creates a continuous need for high cardiac output). Drugs used to treat Paget’s disease include etidronate (Didronel), which slows normal and abnormal bone formation and decreases serum calcium levels. Human calcitonin is also used to treat Paget’s disease; it is a synthetic product that inhibits bone resorption, lowers elevated serum calcium in patients with Paget’s disease, and increases removal of phosphate, calcium, and sodium by the kidney.

CONTRACEPTIVE AGENTS ESTROGEN AND PROGESTINS 1. Estrogen and progestins are hormones that promote the maturation and activity of female reproductive organs. 2. In addition, these hormones promote development of secondary sexual characteristics in females. 3. The principal endogenous estrogen is estradiol. 4. The major progestational hormone is progesterone. 5. Both hormones are produced by the ovaries. 6. During pregnancy, large amounts are also produced by the placenta. 7. Clinical application of the female sex hormones falls into two major categories: contraceptive and noncontraceptive use. 8. For the estrogens, these applications include treatment of menopausal symptoms, osteoporosis, prostatic carcinoma, and carcinoma of the breast. 9. For the progestins, the principal noncontraceptive indications are amenorrhea, dysfunctional uterine bleeding, endometrial carcinoma, and endometriosis. 10. The use of estrogen and progestin for contraception is presented in the last part of this chapter. 11. Estrogen replacement therapy for postmenopausal women is controversial.

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ORAL CONTRACEPTIVE AGENTS 1. Oral contraceptives (OCs) are among the most effective forms of birth control. 2. There are two principal categories of oral contraceptives: those that contain both estrogen and a progestin, known as combination oral contraceptives (COs), and those that contain only progestin, known as “minipills” or progestin-only pills. 3. Of the two groups, the combination pills are by far the most widely used. COs have become one of the most widely prescribed families of drugs, and they are nearly 100% effective, making them one of the most effective forms of birth control available. 4. The COs of have three subgroups: monophasic, biphasic, and triphasic. 5. In a monophasic regimen, the daily estrogen and progestin dosage remains constant throughout the monthly cycle of use. 6. In a biphasic regimen, the estrogen dosage remains constant, but the progestin dosage is increased during the second half of the cycle. 7. In a triphasic regimen, the progestin dosage changes for each phase of the cycle; in one segment, the estrogen dosage varies as well.

◆ Estrogen-Containing Preparations Generic Name

Trade Name

Route

Indications

Estrone

Theelin Aqueous

IM

Estropipate

Ogen

PO, vaginal cream

Conjugated estrogen Estradiol

Premarin Estratab, Menest

PO PO, vaginal cream

Estradiol valerate

Delestrogen

Transdermal

Diethylstilbestrol (DES) Desired effect:

No trade name

PO, IV

Female hypogonadism, prostate cancer Atrophic vaginitis, female hypogonadism, prostate cancer Menopausal symptoms Menopausal symptoms, female hypogonadism, prostate cancer Menopausal symptoms, female hypogonadism, prostate cancer Breast cancer, prostate cancer

Side effects:

In postmenopausal women, estrogen replacement decreases bone loss and reduces the incidence of fracture by increasing calcium absorption; however, there must be pressure on long bones for calcium to be absorbed. Thromboembolic and thrombotic disease, hypertension, photosensitivity, peripheral edema, intolerance to contact lenses. There is no concrete evidence of birth defects related to estrogen or progesterone when taken in small amounts during pregnancy.

Endocrine Drugs ◆ 81

◆ Estrogen-Containing Preparations Generic Name Side effects (continued)

Trade Name

(continued)

Route

Indications

Progesterone is used to treat luteal phase defects in patients undergoing infertility treatment; research has shown that a large number of patients have continued to take oral contraceptives for sometimes months after conception with no documented increase in congenital anomalies despite exposure to both ethinyl estradiol and different progestins. Diethylstilbestrol (DES) (a synthetic preparation possessing estrogenic properties that is several times more potent than natural estrogens and may be given orally) is used therapeutically in the treatment of menopausal disturbances and other disorders due to estrogen deficiency. DES may cause vaginal and cervical cancer in women who were exposed to it during fetal life (i.e., women whose mothers took DES during pregnancy).

Note: Estraderm is available in a transdermal patch formulation. The patch is applied to the skin (not the breast), allowing estrogen to be absorbed through the skin and then directly into the bloodstream. When compared with oral administration, the patches have a significant advantage: the serum level of estrogen produced by the patches more closely resembles premenopausal estrogen levels than do the serum levels produced by oral estrogens.

◆ Progestin-Containing Preparations Generic Name

Trade Name

Route

Indication

Progesterone

No commonly used trade name

IM

Megestrol acetate

Megace

PO

Amenorrhea, dysfunctional uterine bleeding Breast and endometrial cancer

Medroxyprogesterone

Depo-Provera

IM

Desired effects:

Side effects:

Treatment:

Amenorrhea, endometriosis, endometrial cancer, dysfunctional uterine bleeding Progesterone and Megace transform proliferative endometrium into secretary endometrium; inhibit the secretion of pituitary gonadotropins, which prevents follicular maturation and ovulation; inhibit spontaneous uterine contractions. The mechanism of Megace’s antineoplastic activity is unknown, but may be due to a pituitary-mediated anti-luteinizing effect. Sudden partial or complete loss of vision, proptosis, diplopia, migraine, dizziness, thrombophlebitis, cerebrovascular disorders, retinal thrombosis, pulmonary embolism, breakthrough bleeding, spotting, change in menstrual flow, amenorrhea, dysfunctional uterine bleeding. Progesterone and Depo-Provera are used to treat dysfunctional uterine bleeding that occurs when progesterone levels are insufficient to balance the stimulatory influence of estrogen on the endometrium. (continued)

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◆ Progestin-Containing Preparations (continued) Generic Name Treatment (continued)

Nursing implications:

Trade Name

Route

In the absence of sufficient progesterone, estrogen puts the endometrium in a state of continuous proliferation. Since progesterone is unavailable to induce monthly endometrial breakdown, the excessively proliferative endometrium undergoes spontaneous sloughing at irregular intervals. Irregular breakdown of the endometrium can result in periodic episodes of severe menstrual bleeding. Treatment has two objectives: (1) the initial goal is cessation of hemorrhage, and (2) the long-term goal is to establish a regular monthly cycle. Educate patients that the administration of progestins in high doses during the first 4 months of pregnancy has been associated with an increased incidence of birth defects (limb reductions, heart defects, and masculinization of the female fetus); therefore, use of progestins during early pregnancy is not recommended; women who become pregnant while taking progestin should be apprised of the potential risk to the fetus; patients should be told to report any episode of abnormal vaginal bleeding.

Note: Depo-Provera provides three or more months of contraceptive protection.

◆ Other Oral Contraceptives Generic Name Combination OCs Monophasic No generic name No generic name Intravenous sodium iodide Triphasic No generic name No generic name No generic name No generic name Progestin-only OCs Triphasic No generic name

Indication

Trade Name

Lo-Ovral Ortho-Cept Ovcon 50 Ortho-Novum 7/7/7 Yasmin Levlite Aviane

Nor-Q.D.

Endocrine Drugs ◆ 83

NURSING IMPLICATIONS OF ORAL CONTRACEPTIVES 1. Combination OCs have been associated with venous and arterial thromboembolism, pulmonary embolism, myocardial infarction, and thrombotic stroke. 2. Thrombotic disorders are caused by the estrogen component of combination OCs, not by the progestin component. 3. The risk of thromboembolic phenomena from OCs is increased in the presence of other risk factors, especially heavy smoking and a history of thromboembolism. 4. The incidence of hypertension among OC users is three to six times greater than that among nonusers. 5. Oral contraceptives elevate blood pressure by increasing blood levels of both angiotensin (a potent vasoconstrictor) and aldosterone (a hormone that promotes salt and water retention). The risk of hypertension increases with age and with duration of OC use. The risk of cancer from OCs appears to be extremely low. Birth defects can be produced by the mother’s use of estrogen and progestin. By inducing endometrial regression, OCs may decrease or eliminate menstrual flow during the initial months of use. Bleeding and spotting may occur, but if bleeding irregularity persists, the possibility of malignancy should be investigated. 10. Because of their carcinogenic and teratogenic actions, OCs are contraindicated for use during pregnancy. 6. 7. 8. 9.

11. Pregnancy should be ruled out prior to initiation of OC therapy. 12. If pregnancy occurs during OC use, drug administration should cease immediately. OCs enter breast milk and also act to reduce milk production. Therefore, OCs should not be taken by women who are breast-feeding. 13. The incidence of twin births is increased in women who become pregnant shortly after discontinuing OCs. 14. Oral contraceptives can elevate plasma glucose levels. Glucose intolerance is most likely in patients who are diabetics. 15. Progestin-only OCs (also known as “minipills”) contain progestin but have no estrogen. Because they lack estrogen, minipills do not cause thromboembolic disorders, but have most of the other adverse effects associated with combination OCs. 16. Unfortunately, although somewhat safer than combination OCs, the progestinonly preparations are less effective and cause more menstrual irregularity, including breakthrough bleeding, spotting, amenorrhea, inconsistent cycle length, variation in the blood volume, and duration of monthly blood flow. 17. Make patients aware of the following guidelines in the event of missed pills: (1) if one pill is missed, take it as soon as remembered, with the next pill taken

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OTHER TYPES OF CONTRACEPTIVES DEPOT MEDROXYPROGESTERONE ACETATE 1. Following a single IM injection of medroxyprogesterone acetate (MPA; DepoProvera), highly effective contraception for 3 or more months is provided. 2. Injections of 150 mg are repeated every 3 months to provide continuous protection. 3. Adverse effects of MPA are similar to those seen with other progestins.

EMERGENCY POSTCOITAL CONTRACEPTION 1. Postcoital contraceptives, also known as “morning-after” pills, can prevent pregnancy when taken following intercourse. 2. To be effective, these drugs should be taken no later than 72 hours after coitus. 3. Because their side effects can be intense, postcoital contraceptives are not considered substitutes for traditional methods of birth control.

DRUG THERAPY FOR INFERTILITY 1. The majority of drugs used to increase fertility are directed at improving reproductive function in females.

◆ Postcoital Contraceptives Generic Name

Trade Name

Ethinyl estradiol/norgestrel Mifepristone Desired effect:

Ovral RU 486 Prevention of pregnancy by the estrogen in Ovral and RU 486 is used for postcoital contraception and for termination of early pregnancy (abortion) Thromboembolism, stroke, pulmonary embolism, myocardial infarction, anorexia, nausea, vomiting

Side effects:

Endocrine Drugs ◆ 85

◆ Agents Used to Treat Infertility Generic Name

Trade Name

Clomiphene Menotropins Bromocriptine Danazol Desired effects:

Clomid Pergonal Parlodel Danocrine 1. Clomiphene—promotes follicular maturation and ovulation 2. Menotropins—promote follicular maturation and ovulation 3. Bromocriptine—corrects amenorrhea and infertility associated with excessive prolactin secretion 4. Danazol—treats endometriosis and associated infertility Clomid: hot flashes, nausea, bloating, and breast engorgement Pergonal: sudden enlargement of the ovaries Danocrine: deepening of the voice and growth of facial hair

Side effects:

2. Drugs can increase female fertility by helping promote the following: (1) maturation of ovarian follicles, (2) ovulation, (3) production of favorable cervical mucus, (4) control of endometriosis, and (5) reduction of excessive prolactin levels. The ability of drugs to increase fertility in males is limited. In some cases, therapy may improve semen and sperm production.

UTERINE STIMULANTS 1. Uterine contractions can be intensified or diminished with drugs. 2. Drugs that stimulate contractions are known as oxytocics (drugs that inhibit contractions are called tocolytics). 3. There are three types of uterine stimulants: a. Oxytocin: the principal indication for oxytocin is induction of labor. b. Prostaglandins (e.g., dinoprostone): these are primarily used for abortion. c. Ergot alkaloids (oxytocic agents): these are primarily used to control postpartum bleeding. They are also used to control bleeding after abortion.

◆ Uterine Stimulants Generic Name

Trade Name

Oxytocin Ergonovine

Pitocin Ergotrate (continued)

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◆ Uterine Stimulants

(continued)

Generic Name

Trade Name

Methylergonovine (ergot alkaloid) Desired effect:

Methergine Pitocin is used to increase the force, frequency, and duration of uterine contractions; the primary therapeutic use of oxytocin is induction of labor near term. Ergotrate and Methergine are used to control bleeding after delivery of the placenta and to control bleeding after abortion. Pitocin: cardiac arrhythmias, hypertension, subarachnoid hemorrhage, postpartum hemorrhage, uterine rupture, uterine hypertonicity; a most serious but rare side effect is water intoxication, with possible seizures, coma, and maternal death. Ergotrate and Methergine: dizziness, headache, transient hypertension, palpitations, chest pain, nausea, vomiting During oxytocin infusion, constant monitoring is required; the mother should be monitored for uterine contractility (frequency, duration, and intensity), blood pressure, pulse rate and rhythm. In the event of significant maternal or fetal distress, the infusion should be stopped; this will cause contractions to diminish rapidly; complications that usually require interruption of the infusion are (1) elevation of resting uterine pressure above 15–25 mm Hg, (2) contractions that persist for more than 1 minute, (3) contractions that occur more often than every 2–3 minutes, and (4) pronounced alteration in fetal heart rate or rhythm. Ergot alkaloids are contraindicated for women who are pregnant, hypertensive, or hypersensitive to these drugs; ergot alkaloids are also contraindicated for induction of labor and for use in the presence of threatened or ongoing spontaneous abortion.

Side effects:

Nursing implications:

PROSTAGLANDINS 1. Prostaglandins are synthesized in all tissues of the body, where they act as local hormones. 2. Prostaglandin, like oxytocin, can increase the force, frequency, and duration of uterine contractions. 3. Prostaglandins are used to induce abortion. 4. Dinoprost, tromethamine, and dinoprostone are prostaglandins that are used to induce abortion during the second trimester. 5. Side effects include headache, dizziness, hypotension, nausea, vomiting, diarrhea, leg cramps, and joint swelling.

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UTERINE RELAXANTS Uterine relaxants (tocolytics) are given to prevent premature delivery (i.e., delivery prior to the 37th week of gestation).

◆ Uterine Relaxants Generic Name

Trade Name

Ritodrine Treatment: Side effects:

Yutopar Suppression of preterm labor Pulmonary edema, tachycardia, hypotension, hyperglycemia

◆ Drug Therapy for Erectile Dysfunction Generic Name

Trade Name

Sildenafil citrate Tadalafil Vardenafil Desired effect: Side effects:

Viagra Cialis Levitra Penile erection Headache, abnormal vision, dizziness, nasal congestion, dyspepsia, diarrhea, urinary tract infection, rash

Note: Medical help is needed immediately for erection that lasts more than 4 hours. Priapism must be treated as soon as possible or permanent damage can be done to the penis, including the inability to have erections.

Chapter

8

Drugs for Inflammatory and Allergic Disorders

NONSTEROIDAL ANTI-INFLAMMATORY DRUGS 1. The nonsteroidal anti-inflammatory drugs (NSAIDs) are a large and commonly prescribed family of drugs. 2. These drugs are the mainstay of treatment for inflammatory disorders (e.g., arthritis) and are used widely to relieve mild to moderate pain, suppress fever, and relieve symptoms of primary dysmenorrhea. 3. Aspirin belongs to a chemical family known as the salicylates and is also known as acetylsalicylic acid (ASA). 4. Aspirin can be used as an anticoagulant because it suppresses platelet aggregation and can decrease prothrombin production. 5. Reye’s syndrome is a rare but serious illness of childhood that has a mortality rate of 20–30%. Epidemiological data suggest a relationship between Reye’s syndrome and use of aspirin by children who have influenza or chickenpox; however, a direct link has not been established. Because of the possible relationship between aspirin and the development of Reye’s syndrome, it is recommended that aspirin and other NSAIDs be avoided by children and teenagers suspected of having influenza or chickenpox. 88

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◆ Nonsteroidal Anti-Inflammatory Drugs Generic Name

Trade Name

Aspirin Diflunisal Ibuprofen Indomethacin Ketorolac Naproxen sodium Celecoxib Etoricoxib Valdecoxib Desired effects:

Ecotrin, Bayer, others Dolobid Motrin, Advil, others Indocin Toradol Anaprox, Aleve Celebrex Arcoxia Bextra Celebrex and Bextra: Analgesic and anti-inflammatory activities related to inhabitation of the COX-2 enzyme, which is activated in inflammation to cause the signs and symptoms associated with inflammation Aspirin: Gastric distress, nausea, GI bleeding, gastric ulceration, and Reye’s syndrome; aspirin is contraindicated in patients with peptic ulcer disease, bleeding disorders (e.g., hemophilia), vitamin K deficiency, hypoprothrombinemia, and hypersensitivity to aspirin itself or other NSAIDs All NSAIDs may cause gastric irritation. Take these drugs with food or after meals. All of these drugs decrease renal flow and may cause renal failure. In addition, aspirin should be used with extreme caution by pregnant women and by children who have chickenpox or influenza; it should be used with caution when treating the elderly. Other NSAIDs: Adverse effects are minimal; these drugs produce less GI disturbance and gastric bleeding, and cause less inhibition of platelet aggregation than aspirin; all NSAIDs decrease renal blood flow and may cause renal failure as well as the following hematologic disorders: neutropenia, eosinophilia, leukopenia, pancytopenia, thrombocytopenia, agranulocytosis, granulocytopenia, aplastic anemia, decreased hemoglobin or hematocrit, bone marrow depression, menorrhagia. Note that the COX-2 inhibitors Celebrex and Bextra are still on the market but Vioxx, also a COX-2 inhibitor, has been removed from the market due to severe side effects. All NSAIDs suppress inflammation, reduce fever, and relieve mild to moderate pain; they relieve primary dysmenorrhea; they are used to treat arthritis, tendonitis, and bursitis. Name confusion has occurred between Celebrex (celecoxib) and Celexa (citalopram), Xanax (alprazolam), and Cerebyx (fosphenytoin); use caution.

Side effects with nursing implications:

Treatment:

Clinical alert:

Note: Indocin has some serious side effects, including seizures, depression, psychosis, GI ulcerations, and hemorrhage.

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◆ Acetaminophen Generic Name

Trade Name

Acetaminophen Treatment:

Tylenol, others Relief of pain and fever in patients who cannot tolerate the side effects of aspirin (e.g., patients with bleeding disorders or peptic ulcers); because there is no association with Reye’s syndrome, acetaminophen is preferred to aspirin for use by children suspected of having chickenpox or influenza. Side effects are rare at therapeutic levels; the risk of liver injury is increased in chronic alcoholics. Acetaminophen does not cause gastric ulcers or gastric bleeding; it does not inhibit platelet aggregation, decrease renal blood flow, or cause renal failure (as seen with NSAIDs).

Side effects: Nursing implications:

GLUCOCORTICOIDS USED IN NONENDOCRINE DISEASES 1. Glucocorticoids are used to treat both endocrine and nonendocrine disorders. 2. Nonendocrine disorders (asthma, arthritis) require higher doses and are discussed below. 3. Because prolonged high-dose therapy can produce serious adverse effects, the potential benefits of treatment must be weighed carefully against these potentially serious effects. 4. The glucocorticoid drugs (e.g., cortisone, prednisone), which are also known as corticosteroids, are nearly identical to the glucose-regulation steroids produced by the adrenal cortex. 5. Glucocorticoids have two effects: (1) alteration of glucose metabolism is elicited by low doses of steroids; (2) suppression of inflammation occurs with high doses of steroids. 6. In high (pharmacological) doses, these agents are used to treat inflammatory disorders (e.g., asthma, arthritis). 7. Glucocorticoids have an unfavorable impact on protein metabolism. These agents suppress synthesis of proteins from amino acids and divert amino acids for production of glucose. These actions can cause a reduction in muscle mass, thinning of the skin, and a decrease in the protein matrix of bone. Nitrogen balance also becomes negative.

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8. The most consistent effect of glucocorticoids on fat metabolism is stimulation of lipolysis (fat breakdown). Long-term high-dose therapy can cause fat redistribution, resulting in the pot belly, “moon face,” and “buffalo hump” that typify Cushing’s disease. 9. Glucocorticoids are required to maintain the functional integrity of the vascular system. When levels of endogenous glucocorticoids are low, capillaries become more permeable, vasoconstriction is suppressed, and blood pressure falls, as seen in Addison’s disease. 10. Glucocorticoids increase the number of circulating red blood cells. Counts of lymphocytes, eosinophils, basophils, and monocytes are reduced. 11. Synthesis and release of glucocorticoids is regulated by a negative feedback loop. The principal components of this loop are the hypothalamus, the anterior pituitary, and the adrenal cortex. 12. The loop is turned on when stress or some other stimulus from the central nervous system (CNS) acts on the hypothalamus to cause release of corticotropinreleasing factor (CRF). CRF then stimulates the pituitary to release adrenocorticotropic hormone (ACTH), which in turn acts on the adrenal cortex to promote synthesis and release of cortisol. 13. When steroids are administered chronically in large doses, the feedback loop (ACTH) remains continuously suppressed. This persistent inhibition can cause addisonian crisis, especially if the client is stressed (e.g., due to surgery). Treatment for addisonian crisis is IV cortisone, often administered in the form of Solu-Cortef. 14. Adrenal suppression is caused during long-term steroid therapy because the pituitary loses much of its ability of manufacture ACTH, and in response to the prolonged absence of ACTH, the adrenal cortex becomes atrophic and loses its ability to synthesize cortisol and other glucocorticoids. 15. As a result, when prolonged therapy with steroids is discontinued, there is a period during which the adrenal glands are unable to produce glucocorticoids, resulting in addisonian crisis. 16. It may take from a few weeks to more than a year for the adrenal gland to recover and produce glucocorticoids in sufficient quantities to maintain normal body function. 17. When stress is severe (e.g., surgery) these glucocorticoids are essential for supporting life. 18. Accordingly, it is imperative that clients receiving long-term glucocorticoid therapy be given increased doses at times of stress (unless the dosage is already very high). 19. Furthermore, once glucocorticoid use has ceased, supplemental doses will be required whenever stress occurs until recovery of adrenal function is complete.

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◆ Glucocorticoid Agents Generic Name

Trade Name

Route

Short-acting glucocorticoids Cortisone Dexamethasone

Cortone Decadron

PO, IM Oral, topical dermatologic aerosol and gel, ophthalmic suspension PO, IV, IM

Methylprednisolone Prednisone

Long-acting glucocorticoids Hydrocortisone Prednisolone Triamcinolone Nasal corticosteroids Fluticasone, propionate

Medrol, Depo-Medrol, Solu-Medrol No commonly used trade name

PO

Cortef Delta-Cortef Aristocort, Atolone

PO, IM, IV PO PO, IM, inhalant

Flonase

Used as preventive treatment for asthma, not as primary treatment; may take several weeks to work; clean nasal spray adapter weekly; adult: 2 sprays in each nostril daily; approved for children 4–11 years old Used to treat allergic rhinitis in those ≥4 years old; 2 sprays in each nostril daily Used as prophylactic treatment of asthma for patients who require a corticosteroid in those ≥4 years old; 88–220 g twice daily using provided inhalation device Used to reduce swelling in the lungs so more air can move through them Used for the control of bronchial asthma requiring corticosteroids in conjunction with other therapy; intranasal: for relief of symptoms of seasonal or perennial rhinitis that responds poorly to other treatments

Flovent Rotadisk

Flovent Diskus

Fluticasone

Flovent

Dexamethasone sodium phosphate

Decadron Phosphate, Dalalone

NURSING IMPLICATIONS 1. Most clients receiving long-term glucocorticoid therapy should be on a highpotassium, low-sodium diet to counter the potassium-depleting and sodiumretaining effects of the drugs.

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2. Clients should limit intake of alcohol, caffeine, aspirin, and other gastric irritants to minimize peptic ulceration. 3. Long-term therapy may require increased protein intake to decrease the effects of protein catabolism. 4. Glucocorticoids with high mineralocorticoid potency (cortisone, hydrocortisone) can cause significant retention of sodium and water, coupled with depletion of potassium. 5. These mineralocorticoid effects can be especially hazardous for clients with hypertension or congestive heart failure and for clients taking digitalis glycosides. 6. A negative nitrogen balance can result from glucocorticoid-induced breakdown of protein. The patient should be advised to consume a high-protein diet, and should be provided with a diet plan or a list of appropriate foods. 7. Cataracts are a common complication of long-term glucocorticoid therapy. To facilitate early detection, the patient should be encouraged to have an ophthalmologic examination every 6–8 months. Advise the patient to contact the physician if vision becomes cloudy or blurred. 8. Assess and educate the patient regarding increased susceptibility to infection by suppression of the immune system. 9. Long-term glucocorticoid therapy can induce Cushing’s syndrome, whose symptoms are identical to those of naturally occurring Cushing’s disease. Symptoms are hyperglycemia, glycosuria, fluid and electrolyte disturbances, osteoporosis, muscle weakness, cutaneous striations, and lowered resistance to infection. Redistribution of fat produces a large abdomen, “moon face,” and “buffalo hump.” Remember that these signs and symptoms indicate the exact opposite of adrenal insufficiency (Addison’s disease). 10. Observe for signs and symptoms of peptic ulcer disease. 11. Educate clients regarding fluid and electrolyte disturbances (sodium and water retention) and obtain client weight before therapy begins. Also, establish a baseline for hematological values, serum electrolytes, serum glucose, and potassium loss. 12. Osteoporosis is a frequent and serious complication of chronic glucocorticoid therapy. Osteoporosis results from steroids inhibiting the activity of osteoblasts (cells responsible for formation of bone). 13. Educate clients regarding signs and symptoms of hyperglycemia, a side effect of glucocorticoid therapy. 14. Observe and educate clients regarding signs and symptoms of myopathy manifested by muscle weakness. 15. Watch for growth retardation; glucocorticoids can suppress growth in children. 16. Assess and educate clients regarding signs of psychological disturbances (depression, euphoria, mania, and other psychological problems). 17. The intensity of these effects increases with dosage and duration of treatment.

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◆ Chapter 8 18. These toxicities are not seen when dosage is low and treatment is brief (a few days or a week). 19. Withdrawal of glucocorticoids is done slowly. The withdrawal schedule is determined by the degree of adrenal suppression. a. Adrenal insufficiency: monitor for sodium and water loss, hyperkalemia, hypoglycemia, and infection (caused by depressed immune response). b. Instruct the client to report withdrawal symptoms, including weakness, lethargy, malaise, restlessness, psychological despondency, anorexia, and nausea.

DRUG THERAPY FOR RHEUMATOID ARTHRITIS Rheumatoid arthritis is the most common systemic inflammatory disease, affecting between 6 and 9 million Americans. Although the disease can develop at any age, initial symptoms usually appear in the third or fourth decade of life.

DRUG THERAPY FOR ARTHRITIS INCLUDES THREE MAJOR CATEGORIES Drug therapy for arthritis is based on severity of symptoms, the client’s response to treatment, and the client’s ability to tolerate a drug’s side effects. 1. Nonsteroidal anti-inflammatory drugs (NSAIDs) can be subdivided into salicylates (e.g., aspirin) and nonsalicylates (e.g., ibuprofen). They provide rapid relief of symptoms but do not alter disease progression. NSAIDs are presented earlier in this chapter. 2. Glucocorticoid agents are also used, and are also presented earlier in this chapter. 3. Disease-modifying antirheumatic drugs (DMARDs) can be subdivided into: (1) first-choice DMARDs (e.g., hydroxychloroquine, gold salts), and (2) other DMARDs (e.g., methotrexate, cyclophosphamide). These drugs often retard the progression of rheumatoid arthritis. However, the onset of therapeutic effects is delayed, typically for 2–5 months. (Note that DMARDs are more toxic than NSAIDs, and therefore treatment requires rigorous monitoring.)

DISEASE-MODIFYING ANTIRHEUMATIC DRUGS (DMARDS) Gold Salts 1. The beneficial effect of gold salts in treating rheumatoid arthritis has been known since the 1930s. 2. Gold can relieve pain and stiffness, and for some clients may arrest the progression of joint degeneration. 3. The therapeutic effect of gold takes 4–6 months to develop.

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4. Gold preparations are available for IM and oral use. Clients receiving IM therapy require repeated injections over a prolonged period. 5. The oral preparation is more convenient and less toxic than IM gold salts. Unfortunately, the oral preparation is also less effective. Nursing Implications 1. Among the most common reactions are intense pruritus, rashes, and stomatitis (lesions of the oral cavity). 2. Renal toxicity, manifested as proteinuria (cloudy urine), thrombocytopenia, aplastic anemia, agranulocytosis (acute low white cell count), and leukopenia (abnormal decrease in white blood cells) are rare. 3. Other serious toxicities include encephalitis, hepatitis, severe hypotension, and peripheral neuritis. 4. Frequent laboratory tests and clinical evaluations are required. 5. A baseline assessment should include the extent of joint involvement, discomfort, and mobility, hepatic and renal function values, WBC count, platelet count, and urinalysis.

Hydroxychloroquine (Plaquenil) Hydroxychloroquine (Plaquenil), a drug with antimalarial action, can produce remission in patients with rheumatoid arthritis. The drug may be prescribed early in the course of the disease in an effort to delay joint degeneration. Nursing Implications 1. Like gold salts, hydroxychloroquine has a delayed onset of action; full therapeutic effects take 3–6 months to develop. 2. Concurrent therapy with anti-inflammatory agents (NSAIDs or steroids) is indicated during the latency period. 3. The mechanism by which gold therapy or hydroxychloroquine acts is unknown. 4. The most serious toxicity is retinal damage. Retinopathy may be irreversible and can produce blindness.

Cytoxan, Methotrexate, and Imuran 1. The anticancer drugs Cytoxan (cyclophosphamide), methotrexate, and Imuran (azathioprine) can relieve symptoms of severe arthritis. In some cases, prolonged remission may be induced. Two of these drugs, cyclophosphamide and azathioprine, are considered very toxic, and are generally reserved for patients who have not responded to safer medications. Methotrexate (no commonly used trade name) is the fastest acting of the disease-modifying antirheumatic drugs; therapeutic effects may be seen as early as after 3–6 weeks. 2. Many physicians consider methotrexate the first-line drug among the DMARDs.

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◆ Chapter 8 3. Major toxicities are hepatic fibrosis, bone marrow depression, gastrointestinal ulceration, and pneumonitis. Note: Methotrexate is also used to treat ectopic pregnancies and can be used for medical abortions. The drug works by blocking cell growth. Unlike a surgical abortion, in which the fetal embryo is scraped or suctioned from the uterus, a woman simply takes the drug and the embryo is aborted, much like a miscarriage.

Nursing Implications 1. Periodic tests of liver and kidney function are mandatory, as are complete blood counts and platelet counts for all clients on anticancer drugs. 2. Assess clients for infections, as anticancer drugs depress the bone marrow. 3. Methotrexate can cause fetal death and congenital abnormalities; therefore, the drug is contraindicated during pregnancy. 4. Methotrexate may be administered once weekly, beginning at 5 mg. The dose may be gradually increased to a maximum of 15–20 mg. 5. Azathioprine (Imuran): the antiarthritic effects of this drug are equivalent to those of gold salts and hydroxychloroquine. This drug is classified as an immunosuppressant. Benefits are derived from immunosuppressive and anti-inflammatory actions. Imuran is also employed to prevent organ rejection. 6. Serious toxicities of Imuran include hepatitis and blood disorders (leukopenia, thrombocytopenia, anemia). Because of these severe side effects, the drug is reserved for patients with life-threatening complications. 7. Cytoxan as a treatment for rheumatoid arthritis is still under investigation. The drug is considered more toxic than methotrexate or Imuran. Serious toxicities include marrow depression, sterility, hemorrhagic cystitis, and mucous membrane lesions.

DRUG THERAPY FOR GOUT 1. Gout is a recurrent inflammatory disorder characterized by hyperuricemia (high blood levels of uric acid) and episodes of severe joint pain, typically in the large toe. 2. Foods high in purines, which aggravate gout, include kidney, liver, poultry, fish, sweetbreads (the thymus gland of an animal such as a cow), anchovies, sardines, and gravies. 3. Six principal drugs are employed to treat gout. Two of these agents, colchicine and indomethacin (Indocin), relieve inflammation. 4. The other four agents are allopurinol (Zyloprim), phenylbutazone (Butazolidin), probenecid (Benemid), and sulfinpyrazone (Anturane). These are used to decrease uric acid.

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5. Allopurinol is generally well tolerated. The most serious toxicity is a rare, but potentially fatal, hypersensitivity syndrome, characterized by rash, fever, and dysfunction of the liver and kidneys. 6. Like other NSAIDs, indomethacin, colchicine, allopurinol, probenecid, and phenylbutazone may cause gastrointestinal reactions (nausea, vomiting, diarrhea, abdominal discomfort).

◆ Agents Used to Treat Gout and Gouty Arthritis Generic Name

Trade Name

Allopurinol Desired effect: Side effects:

Zyloprim Decrease uric acid Rash, renal failure, bone marrow depression, hepatitis, GI disturbance Benemid Headache, nausea, vomiting, urinary frequency, aplastic anemia, GI disturbance

Probenecid Side effects:

Phenylbutazone Side effects: Sulfinpyrazone Side effects: Colchicine Indomethacin Desired effect: Side effects:

Butazolidin Headache, dizziness, edema, hearing loss, aplastic anemia, GI disturbance Anturane Rash, kidney stones, nausea, vomiting, blood dyscrasias, GI disturbance No commonly used trade name Indocin Relieve inflammation Gastric ulceration, bone marrow depression, aplastic anemia, mental confusion, peripheral neuritis

Chapter

9

Respiratory Tract Drugs

DRUG THERAPY FOR ASTHMA 1. Asthma is a very common disorder that affects both children and adults. In the United States, asthma affects between 10 and 20 million people. 2. Unfortunately, there is no cure for asthma; drugs can only provide symptomatic relief. 3. Beta-2 adrenergic agonists (e.g., terbutaline [Brethine], albuterol [Ventolin]) are a mainstay of antiasthmatic therapy. These drugs are taken by practically all clients who experience asthma attacks. 4. For treatment of asthma, beta-2 agonists are usually administered by inhalation. However, preparations for oral and parenteral use are also available. 5. Adrenergic agonists are discussed in Chapter 2. In this chapter, discussion of adrenergic agonists is limited to their use in treating asthma. 6. Drugs used to treat respiratory infections are presented in Chapter 12.

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Respiratory Tract Drugs ◆ 99

◆ Beta-2 Adrenergic Agonists (Synthetic Catecholamines) Generic Name

Trade Name

Albuterol Epinephrine (adrenaline) Isoetharine Theophylline Metaproterenol Terbutaline Salmeterol xinafoate Formoterol fumarate Pirbuterol acetate Treatment: Beta-2 Adrenergic Agonists Desired effects: Side effects:

Proventil, Ventolin AsthmaNefrin Bronkosol Theo-Dur Alupent Brethine Serevent Diskus Foradil Aerolizer Maxair Autohaler Asthma, chronic obstructive pulmonary disease (COPD)

Desired effects: Side effects: Desired effects: Side effects: Desired effects:

Side effects: Desired effects: Side effects: Desired effects: Side effects: Desired effects: Side effects: Desired effects:

• Proventil, Ventolin: bronchodilator, vasodilator Restlessness, apprehension, anxiety, fear, insomnia, tremors, irritability, cardiac arrhythmias, sweating • Epinephrine: bronchodilator, antiasthmatic, cardiac stimulant, mydriatic, nasal decongestant, vasopressor Restlessness, apprehension, anxiety, fear, insomnia, tremors, irritability, cardiac arrhythmias, sweating, tachycardia • Bronkosol: bronchodilator Irritability (especially in children) restlessness, dizziness, severe depression, life-threatening arrhythmias, loss of appetite • Theophylline Sympathetic relief or prevention of bronchial asthma and reversible bronchial spasms associated with chronic bronchitis and emphysema Irritability (especially in children), restlessness, life-threatening ventricle arrhythmias, respiratory arrest, proteinuria, loss of appetite • Alupent: bronchodilator Restlessness, apprehension, anxiety, fear bronchospasm • Brethine: bronchodilator Restlessness, apprehension, anxiety, fear, cardiac arrhythmias, palpitations, respiratory difficulties • Serevent Diskus: bronchodilator; also inhibits the release of inflammatory mediators in the lung, blocking swelling and inflammation Headache, tremor, tachycardia, palpitations, hypertension, bronchospasm • Foradil Aerolizer: bronchodilator; also inhibits the release of inflammatory mediators in the lung, blocking swelling and inflammation (continued)

100 ◆ Chapter 9

◆ Beta-2 Adrenergic Agonists (Synthetic Catecholamines) (continued) Generic Name

Trade Name

Side effects:

Tremor, dizziness, insomnia, headache, nervousness, hypertension, tachycardia, chest pain, bronchitis, viral infections (most likely in children) • Maxair Autohaler: bronchodilator (and vasodilator); at high doses beta-2 selectivity is lost and the drug also acts on beta-1 receptors to cause typical sympathomimetic cardiac effects

Desired effects:

◆ Antiasthmatic Glucocorticoids Generic Name

Trade Name (Route)

Prednisone Budesonide Mometasone furoate Dexamethasone sodium phosphate Budesonide Beclomethasone Triamcinolone acetonide Desired effect:

Deltasone (PO) Rhinocort (inhalation) Nasonex (inhalation) Decadron Phosphate (inhalation, IM, IV)

Side effects:

Pulmicort, Rhinocort Aqua (inhalation) Vanceril, Vanceril Double Strength (inhalation) Azmacort (inhalation, IM) Control of bronchial asthma; corticosteroids are used in conjunction with other therapy; prophylactic therapy may also be used. Adverse effects depend on dose, route, and duration of therapy; inhalational adverse effects include nasal irritation, fungal infections, epistaxis, rebound congestion, and perforation of nasal septum

Note: Doctors usually recommended inhaled corticosteroids instead of oral steroids because the mist goes directly into the lungs, and less of the medication reaches other parts of the body, keeping side effects to a minimum. Most patients need to use the inhaler several times a day, and the proper dose is the smallest one that keeps the patient free of attacks. Heavy use of these inhalers may slow growth in children, perhaps by a third of an inch a year.

TEACHING POINTS FOR CLIENTS Rinse your mouth after inhalant therapy. Use the product exactly as prescribed, and do not stop taking the drug without consulting your health care provider. The drug should not be stopped abruptly but must be slowly tapered.

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Teaching Patients How to Use Devices that Help Monitor and Control Asthma 1. Peak flow meter: Teach the patient to blow hard and quickly into the instrument, which slides a gauge to within one of three zones: green for health, yellow for caution, and red for medical alert. 2. Metered-dose inhaler: Teach the patient to breathe in, press the canister down into the mouthpiece, and continue to inhale the medication as it is released. Inhalers deliver metered doses of medicine to the lungs. 3. Spacer: Teach the patient to spray medication into the plastic bag instead of directly into the mouth, and the medication is inhaled via a mouthpiece without depositing medicine directly in the mouth and throat. The spacer works by allowing the patient to inhale medication more slowly.

◆ Other Antiasthmatic and Antiallergenic Agents Generic Name

Trade Name

Nedocromil sodium Cromolyn sodium Desired effects:

Tilade (inhalation) Intal (inhalation) Decreases the release of histamine and blocks the overall inflammatory reaction Cough, nasal congestion, headache, fatigue, bad taste

Side effects:

Note: Intal and Tilade are not as powerful as the inhaled corticosteroids.

Leukotriene formation inhibitors Zileuton Montelukast sodium Zafirlukast Desired effects:

Treatment: Side effects:

Zyflo (PO) Singulair (PO) Accolate (PO) Decrease inflammation, edema, mucus secretion, and bronchoconstriction associated with asthma; this is accomplished by selectively and competitively blocking the receptor that causes leukotriene formation, thus blocking many of the signs and symptoms of asthma, including neutrophil and eosinophil migration, neutrophil and monocyte aggregation, leukocyte adhesion, increased capillary permeability, and smooth muscle contraction Asthma, COPD Alopecia, edema, Cushing’s syndrome, epistaxis, nasal irritation, fungal infection, paresthesias, nervousness, weight gain, hyperglycemia

Note: Liver enzyme elevation is an adverse side effect of Zyflo and Accolate.

(continued)

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◆ Other Antiasthmatic and Antiallergenic Agents (continued) Generic Name Antihistamines Loratadine Fexofenadine Brompheniramine maleate Chlorpheniramine maleate Cetirizine Diphenhydramine Dimenhydrinate Hydroxyzine Desired effect: Treatment:

Side effects: Desired effects:

Side effects:

Desired effects:

Side effects: Desired effects:

Side effects: Desired effects:

Side effects:

Trade Name Claritin Allegra No trade name Chlor-Trimeton Zyrtec Benadryl Dimetabs Vistaril • Claritin: competitively blocks the effects of histamine at H1 -receptor sites; has anticholinergic (atropinelike), antipruritic, and sedative effects Symptomatic relief of perennial and seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, and mild uncomplicated urticaria and angioedema Drowsiness, headache, nervousness, dizziness, depression, drowsiness, palpitations, increased appetite, fever, weight gain Allegra, Chlor-Trimeton, Benadryl: competitively block the effects of histamine at H1 -receptor sites; anticholinergic (atropinelike), antipruritic, and sedative effects Drowsiness, sedation, dizziness, disturbed coordination, fatigue, anaphylactic shock, hemolytic anemia, thickening of bronchial secretions • Zyrtec: potent histamine H1 -receptor antagonist; inhibits histamine release and eosinophil chemotaxis during inflammation, leading to reduced swelling and decreased inflammatory response Somnolence, sedation, bronchospasm, palpitation • Dimetabs: antihistamine with antiemetic and anticholinergic activity; depresses hyperstimulated labyrinthine function; may block synapses in the vomiting center; peripheral anticholinergic effects may contribute to anti–motion sickness efficacy Drowsiness, confusion, nervousness, restlessness, headache, dizziness, vertigo, insomnia, weakness of hands, seizures • Atarax, Vistaril: mechanism of action not understood; action may be due to suppression of subcortical areas of the CNS; has clinically demonstrated antihistaminic, analgesic, and bronchodilator activity Drowsiness, involuntary motor activity including seizures, dry mouth, urinary retention, wheezing, dyspnea

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METHYLXANTHINES Caffeine 1. Caffeine is the most familiar member of this family. 2. Caffeine is present in tea, coffee, cola drinks, and cocoa. 3. In low doses, caffeine decreases drowsiness and fatigue and increases the capacity for prolonged intellectual exertion. With increasing dosage, caffeine produces nervousness, insomnia, and tremors. 4. High doses of caffeine stimulate the heart. When caffeine-containing beverages are consumed in excessive quantities, arrhythmias may result. 5. In the peripheral blood vessels caffeine promotes vasodilation, and in the CNS it is an effective stimulant. 6. Caffeine and other methylxanthines promote bronchodilation. 7. Caffeine is a diuretic. The mechanism by which it increases urine formation is not fully understood. 8. Caffeine is used primarily as an aid to stay awake.

Theophylline 1. Theophylline (Bronkodyl, others) is the principal methylxanthine employed to treat asthma. Benefits derive primarily from bronchodilation. 2. Theophylline has a narrow therapeutic range, and dosage must be carefully controlled. 3. The drug is usually administered by mouth. 4. Side effects include nervousness, anxiety, and tachycardia.

Aminophylline 1. Aminophylline (Truphylline) is a theophylline salt that is considered more soluble than theophylline itself. 2. Because of its relatively high solubility, aminophylline is the preferred form of theophylline for intravenous use.

Cromolyn Sodium 1. Cromolyn sodium (Intal) is a very safe and effective drug for prophylaxis of asthma, but is not useful for aborting an ongoing asthma attack. Administration is by inhalation. 2. Cromolyn is used for prophylactic therapy of mild to moderate chronic asthma. 3. The drug produces adequate control in 60–70% of clients.

104 ◆ Chapter 9 4. When administered on a regular schedule, cromolyn reduces both the intensity and frequency of attacks. 5. Adverse effects: cromolyn sodium is the safest of all antiasthmatic medications. The most common reactions are wheezing and coughing in response to inhalation of powdered cromolyn.

Glucocorticoids 1. Glucocorticoids (e.g., prednisone) are the most effective antiasthmatic drugs available. The drugs can be administered orally, intravenously, or by inhalation. 2. Glucocorticoids reduce symptoms of asthma primarily by suppressing inflammation. 3. As a result of suppressing inflammation, glucocorticoids reduce bronchial hyperactivity. In addition to reducing inflammation, glucocorticoids decrease airway mucus production and increase the number of bronchial beta-2 adrenergic receptors, as well as their responsiveness to beta-2 agonists. 4. Glucocorticoids are used for prophylaxis in clients with chronic asthma. 5. Inhalational glucocorticoids are now considered a first-line therapy for asthma. 6. Oral glucocorticoids are reserved for clients with severe asthma. Because of their potential for toxicity, these drugs are prescribed only when symptoms cannot be controlled with safer medications (e.g., beta-2 agonists, theophylline, aminophylline). Because the risk of toxicity increases with duration of use, treatment should be as short as possible. 7. Possible adverse effects from prolonged use of oral glucocorticoids include osteoporosis, hyperglycemia, peptic ulcer disease, and in young clients, suppression of growth. 8. Adrenal suppression is of particular concern, as discussed in Chapter 8.

Chapter

10

Gastrointestinal Drugs

DRUGS FOR PEPTIC ULCER DISEASE 1. Despite commonly held beliefs, dietary factors play only a minor role in ulcer management. The traditional “ulcer diet” consisting of bland foods does not increase healing. There is also no convincing evidence that caffeine-containing beverages promote ulcer formation or interfere with recovery. 2. Smoking is associated with an increased incidence of ulcers; it also retards recovery. Accordingly, cigarettes should be avoided. 3. Because of their ulcerogenic actions, aspirin and other NSAIDs should be avoided. 4. Stress and anxiety may aggravate an existing ulcer. 5. Antiulcer drugs fall into five major classes: (1) antisecretory agents (e.g., Tagamet), (2) agents that enhance mucosal protection (e.g., Carafate), (3) antisecretory agents that enhance mucosal defense (e.g., Cytotec), (4) antacids (e.g., Amphojel), and (5) antibiotics (e.g., Flagyl).

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◆ Antiulcer Agents Generic Name

Trade Name

Antisecretory agents: Histamine2 (H2 )-antagonists Cimetidine Tagamet Famotidine Pepcid Nizatidine Axid Ranitidine Zantac Desired effects: Inhibits the action of histamine at the H2 receptors of the stomach and reduces total pepsin output; Tagamet is available over-the-counter at one-half the prescription strength. Major side effects: Cardiac arrest, impotence (reversible), dizziness, peripheral neuropathy, hallucinations, confusion Nursing implications: Take with meals and at bedtime; therapy may be continued for 4–6 weeks or longer; teach patients to have regular follow-up care to evaluate their response; educate patients about side effects and tell them to report side effects to the health caregiver. Antisecretory agents: Proton pump inhibitors Omeprazole Prilosec Lansoprazole Prevacid Esomeprazole Nexium magnesium Rabeprazole Aciphex Desired effects: Suppress gastric acid secretion by specific inhibition of the hydrogen-potassium-ATPase enzyme system at the secretory surface of the gastric parietal cells, blocking the final step of acid production Major side effects: Dizziness, somnolence, headache, confusion, diarrhea, sexual impotence (reversible), somnolence, insomnia, diarrhea, constipation Nursing implications: Tell the patient to take the drug 1 hour before meals; swallow the capsules whole; do not chew or crush; if the patient cannot swallow the capsule, it can be opened and the contents sprinkled in applesauce or mixed in tap water, orange juice, or yogurt; these drugs need to be taken for 4–8 weeks. Note: All antisecretory agents are used for the treatment of active duodenal ulcers, short-term treatment of benign gastric ulcers, to treat pathologic hypersecretory conditions (e.g., Zollinger-Ellison syndrome), erosive GERD, and for relief of heartburn and acid indigestion. They are also used for short-term treatment (4–8 weeks) for erosive esophagitis (diagnosed by endoscopy) and symptomatic gastroesophageal reflux disease.

Antisecretory agent that enhances mucosal defenses Misoprostol Cytotec Desired effects: A synthetic prostaglandin E1 analogue, this mucosal defense agent: (1) suppresses secretion of gastric acid, (2) promotes secretion of bicarbonate and cytoprotective mucus, and (3) maintains submucosal blood flow (by promoting vasodilation), thus protecting the lining of the stomach. (continued)

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◆ Antiulcer Agents (continued) Generic Name

Trade Name

Major side effects:

Nausea, diarrhea, abdominal pain, flatulence, dyspepsia, constipation, miscarriage, excessive bleeding, spotting, cramping, hypermenorrhea, menstrual disorders, dysmenorrhea Prevention of NSAID-induced gastric ulcers, including those caused by aspirin Give to patients at high risk for developing NSAID-induced ulcers; give for the full period of NSAID use; arrange for serum pregnancy tests for any women of childbearing age; they must have a negative test within 2 weeks of beginning therapy

Treatment: Nursing implications:

Mucosal protectants Sucralfate Bismuth Desired effects:

Major side effects:

Treatment:

Nursing implications:

Antacids Aluminum hydroxide Magnesium hydroxide Magaldrate Calcium carbonate Desired effects:

Carafate Pepto-Bismol Forms an ulcer-adherent complex at duodenal ulcer sites, protecting the ulcer from acid, pepsin, and bile salts, thereby promoting ulcer healing; also inhibits pepsin activity in gastric juices Carafate: dizziness, vertigo, rash, pruritus, constipation, diarrhea, dry mouth, gastric discomfort; Pepto-Bismol: darkening of stools, and fecal impaction in infants and debilitated patients, salicylate toxicity, ringing in the ears, rapid respirations Pepto-Bismol: indigestion, nausea, vomiting, and control of traveler’s diarrhea within 24 hours; relief of gas pain and abdominal cramps; Carafate: short-term treatment of duodenal ulcers, up to 8 weeks; maintenance therapy for duodenal ulcer at reduced dosage after healing; treatment of oral and esophageal ulcers due to radiation, chemotherapy, and sclerotherapy Carafate: teach patients to take the drug on an empty stomach, 1 hour before or 2 hours after meals and at bedtime; administer antacids between doses of Carafate, not within 30 minutes before or after Carafate; Pepto-Bismol: instruct patients to shake liquid well before administration, have patient chew tablets thoroughly or allow to dissolve in the mouth; do not swallow whole; discontinue drug if any sign of salicylate toxicity (e.g., ringing in the ears) occurs Amphojel, others Maalox, others Riopan, others Tums, others Neutralizes or reduces gastric acidity, resulting in an increase in the pH of the stomach and duodenal bulb and inhibition of the proteolytic activity of pepsin, which protects the lining of the stomach (continued)

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◆ Antiulcer Agents (continued) Generic Name

Trade Name

Major side effects:

Antacids figure in numerous drug interactions owing to their action on gastric pH (increased) and their propensity to bind with other drugs to form poorly absorbed complexes; decreases pharmacologic effects of corticosteroids, diflunisal, digoxin, iron, isoniazid, penicillamine, phenothiazine, ranitidine, and tetracycline; increases effect of benzodiazepines; major side effects include a change in bowel habits (diarrhea or constipation), nausea, vomiting, alkalosis, and hypermagnesemia. Symptomatic relief of upset stomach associated with hyperacidity; hyperacidity associated with peptic ulcers, gastritis, peptic esophagitis, hiatal hernia Give hourly for the first 2 weeks when used for acute peptic ulcer; during the healing stage, give 1–3 hours after meals; do not administer oral drugs within 1–2 hours of antacid administration

Treatment: Nursing implications:

Antibiotics Metronidazole Tetracycline Amoxicillin Clarithromycin Desired effects: Major side effects:

Flagyl, others Cyclopar, others Augmentin, others Biaxin Inhibits protein synthesis in susceptible bacteria, causing cell death Flagyl: major side effects include headache, dizziness, ataxia, darkened urine, and peripheral neuropathy; Cyclopar: major side effects include discoloration and inadequate calcification of primary teeth of fetuses if used by pregnant women, thrombocytopenia, leukopenia, hemolytic anemia, nausea, and vomiting; Augmentin: major side effects include stomatitis, gastritis, nausea, vomiting, and diarrhea; Biaxin: major side effects include hepatotoxicity, stomatitis, anorexia, nausea, and vomiting

Note: There is a strong association between Helicobacter pylori infections and peptic ulcer disease. H. pylori is present in 95% of clients with duodenal ulcers and 75% of clients with gastric ulcers. Furthermore, eradication of the bacteria promotes ulcer healing and minimizes recurrences. Although the mechanism by which H. pylori promotes ulcers has not been firmly established, research has shown a definite association. The regimen for H. pylori is two or more antibiotics given concurrently, combined with a proton pump inhibitor or an H2 -receptor antagonist for 7–14 days.

LAXATIVES 1. The term laxative effect refers to production of a soft, formed stool over a period of 1 or more days. 2. 3. 4. 5.

The term catharsis applies when evacuation of the bowel is liquid and prompt. A laxative effect is relatively mild, whereas catharsis is more intense. The principal function of the colon is to absorb water and electrolytes. Proper function of the bowel is highly dependent on dietary fiber intake.

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6. The best source of fiber is bran. Fiber can also be obtained from fruits and vegetables. 7. Laxatives can be very beneficial when used for valid reasons. 8. By softening the stool, laxatives can reduce the painful elimination that can be associated with hemorrhoids and other anorectal lesions. 9. In clients with cardiovascular diseases (e.g., myocardial infarction, aneurysm), softening of the stool decreases the strain needed to defecate, thereby avoiding danger of Valsalva’s maneuver, which causes increased intrathoracic pressure and slowing of the pulse, increasing the return of blood to the heart and venous pressure. 10. In geriatric clients, high-fiber diets and exercise should be encouraged as a means of maintaining normal bowel movements. 11. When laxatives are employed habitually, the colon becomes dependent on the laxatives and defecation will not occur without their use. 12. Constipation is treated by establishing good health habits: consuming regular meals with ample fiber and a consistent time for elimination, along with relaxation, exercise, and adequate fluid intake (at least 1000 mL/day). 13. Water needs are greater in clients with decreased renal concentrating ability (such as the elderly) since relatively more water is required to eliminate waste.

CLASSIFICATION OF LAXATIVES 1. Bulk-forming agents (e.g., Metamucil) have actions and effects very similar to those of dietary fiber. a. Bulk-forming laxatives are preferred agents for temporary treatment of constipation. b. Bulk-forming laxatives are widely used by clients with diverticulosis and irritable bowel syndrome. c. In addition, by altering fecal consistency, these agents can provide symptomatic relief of diarrhea and can reduce discomfort and inconvenience for clients with an ileostomy or colostomy. d. Adverse effects: Since the bulk-forming agents are not absorbed, systemic reactions are rare. Esophageal or intestinal obstruction can occur if these agents are swallowed in the absence of sufficient water. To avoid this effect, bulk-forming laxatives should be administered with a full glass of water or juice. e. Excessive intake of dietary fiber over several months can cause serious damage to the colon. 2. Surfactants (e.g., Colace) produce a soft stool several days after the onset of treatment. Administration of all surfactants should be accompanied by a full glass of water.

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◆ Chapter 10 3. Contact laxatives (e.g., Dulcolax, castor oil) are widely used and abused by the general public. The contact laxatives act on the intestinal wall to produce a net increase in the amount of fluid and electrolytes within the intestinal lumen. 4. Saline laxatives (e.g., milk of magnesia, magnesium hydroxide) are poorly absorbed salts whose osmotic action draws water into the intestinal lumen. Accumulation of fluid causes the fecal mass to soften and swell; swelling, in turn, stretches the intestinal wall and thereby stimulates peristalsis.

MISCELLANEOUS GASTROINTESTINAL DRUGS ANTIEMETICS 1. Emesis (vomiting) is a complex reflex brought about by activation of the vomiting center, a nucleus of neurons located in the medulla oblongata. 2. Certain stimuli (e.g., gastrointestinal irritation) activate the vomiting center directly. 3. A major application of the antiemetics is to suppress nausea and vomiting associated with cancer chemotherapy. For clients undergoing cancer chemotherapy, antiemetic therapy offers three major benefits: (1) reducing anticipatory nausea and vomiting, (2) preventing the malnutrition and dehydration that can be caused by frequent nausea and vomiting, and (3) reducing discomfort, thereby increasing compliance with the cancer chemotherapeutic program.

◆ Antiemetics Generic Name Phenothiazines Chlorpromazine Fluphenazine Prochlorperazine Thiethylperazine Butyrophenones Haloperidol Antihistamines Dimenhydrinate Diphenhydramine Hydroxyzine Meclizine Promethazine

Trade Name

Thorazine Prolixin Compazine Torecan Haldol Dramamine Benadryl Vistaril, Atarax Antivert Phenergan

Gastrointestinal Drugs

◆ Antiemetics

(continued)

Generic Name

Trade Name

• Others Metoclopramide Scopolamine Trimethobenzamide Lorazepam Diazepam • Glucocorticoids Dexamethasone Methylprednisolone Ondansetron Treatment:

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Reglan No commonly used trade name Tigan Ativan Valium Decadron Solu-Medrol Zofran • A phenothiazine (e.g., Thorazine) suppresses emesis by blocking dopamine receptors in the medulla oblongata, a trigger zone for monitoring; it is useful for postoperative nausea and vomiting, and for emesis caused by chemotherapy, radiation therapy, and toxins. • Butyrophenones (e.g., Haldol) suppress emesis by acting as a strong anticholinergic blocking agent; it blocks dopamine receptors in the chemoreceptor trigger zone (CTZ); the CTZ is the activating center for vomiting located in the medulla oblongata. • Antihistamines (e.g., Dramamine) are used to treat motion sickness; the mechanism by which these drugs suppress emesis associated with motion sickness is unclear. • Metoclopramide (e.g., Reglan) has two beneficial actions: (1) it blocks dopamine receptors in the CTZ, thereby suppressing emesis, and (2) it increases upper GI motility by enhancing the action of acetylcholine; Reglan is a drug of choice for suppressing nausea and vomiting caused by highly emetic anticancer agents (e.g., cisplatin, dacarbazine); in addition, Reglan is given to suppress postoperative emesis and emesis caused by radiation therapy, toxins, and opioids. • Scopolamine, a muscarinic antagonist, is the most effective drug for prophylaxis and treatment of emesis associated with motion sickness. • Tigan acts to suppress emesis by blocking the CTZ. • Benzodiazepines (e.g., Valium, Ativan) are used to alleviate nausea and vomiting associated with cancer chemotherapy; the antiemetic effect of diazepam derives primarily from suppression of anxiety; Ativan is beneficial because of its ability to produce antegrade amnesia. • Glucocorticoids (e.g., Decadron, Solu-Medrol) have been employed investigationally to treat emesis brought on by cancer chemotherapy; clinical experience has shown these drugs to be effective alone and in combination with other antiemetics; the mechanism by which glucocorticoids suppress emesis is not known; both dexamethasone (Decadron) and methylprednisolone (Solu-Medrol) are administered intravenously. (continued)

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◆ Antiemetics (continued) Generic Name

Trade Name

Treatment: (continued)

• Ondansetron (Zofran) is a new drug used to suppress nausea and vomiting associated with cancer chemotherapy; this drug acts by blocking serotonin receptors in the medulla oblongata on the vagal neurons in the upper GI tract; Zofran has proved to be very effective. • Phenothiazines (e.g., Thorazine) can produce a variety of serious side effects; these include hypotension, sedation, extrapyramidal reactions, and anticholinergic effects. • Butyrophenones (e.g., Haldol) have potential side effects similar to those of the phenothiazines: extrapyramidal reactions, sedation, and hypotension. • Metoclopramide (e.g., Reglan) side effects include extrapyramidal reactions (especially in children), diarrhea, and sedation. • Antihistamines (e.g., Vistaril, Atarax) side effects include drowsiness, dry mouth, ataxia, and dizziness. • Common side effects of scopolamine and Atarax include sedation, dizziness, orthostatic hypotension, dry mouth, constipation, headache, and tachycardia. • Side effects of glucocorticoids (e.g., Decadron) include depression, euphoria, hypertension, anorexia, decreased wound healing, ecchymoses, adrenal suppression, and hyperglycemia. • Side effects of benzodiazepines (e.g., Valium, Ativan) include drowsiness, sedation, depression, lethargy, apathy, fatigue, confusion, bradycardia, tachycardia, and drug dependence. • Side effects of dexamethasone (Decadron) and methylprednisolone (Solu-Medrol) include vertigo, headache, euphoria, mood swings, depression, psychosis, immunosuppression, masking of infections, impaired wound healing, and adrenal cortex suppression. • Side effects of ondansetron (e.g., Zofran) are headache and diarrhea.

Side effects:

Notes: Antivert is also used for dizziness and motion sickness. It is used most often to treat nausea and vomiting associated with Meni ´ ere ` disease.

Benzodiazepines and glucocorticoids are used before administration of cancer chemotherapy.

ANTIDIARRHEAL AGENTS Opioids are the most effective antidiarrheal drugs. By stimulating opioid receptors in the GI tract, these agents suppress peristalsis, thereby facilitating absorption of water and electrolytes. As a result, the fluidity and volume of stools are reduced, as is frequency of defecation.

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◆ Opioids Used to Treat Diarrhea Generic Name

Trade Name

Diphenoxylate (plus atropine) Loperamide Paregoric Desired effects: Side effects:

Lomotil

Treatment: Nursing implications:

Imodium No commonly used trade name Decrease GI peristalsis Lomotil: drowsiness, headache, paralytic ileus, toxic megacolon, and sedation Imodium: toxic megacolon, respiratory depression, drowsiness Paregoric (which is camphorated tincture of opium and contains 0.4 mg morphine/mL): depression, dizziness, drowsiness, fainting, and constipation Diarrhea Advise patients that constipation can result from overuse of these drugs; encourage patients to drink clear liquids and not to ingest fried foods or milk products until after diarrhea has stopped; monitor the frequency of bowel movements and bowel sounds; educate patients to notify health caregiver if intestinal hypoactivity occurs when taking these drugs.

DRUGS FOR INFLAMMATORY BOWEL DISEASE 1. Inflammatory bowel disease has two principal forms: Crohn’s disease and ulcerative colitis. 2. Sulfasalazine (Azulfidine) is most effective in the treatment of acute episodes of mild to moderate ulcerative colitis. 3. Azulfidine may also benefit clients with acute Crohn’s disease. 4. Adverse side effects include nausea, fever, anemia, and agranulocytosis (acute low white cell count). 5. Glucocorticoids can relieve symptoms of ulcerative colitis and Crohn’s disease. Benefits derive from the anti-inflammatory action of these drugs. As discussed in Chapter 8, long-term use of glucocorticoids can cause severe adverse effects, including adrenal cortex suppression, osteoporosis, increased susceptibility to infection, and a Cushing’s-like effect. 6. Immunosuppressive agents are also use to treat Crohn’s disease. Drugs such as Imuran, Cytoxan, and methotrexate are used to suppress inflammation. Side effects include nausea, vomiting, hepatotoxicity, leukopenia, thrombocytopenia, and carcinogenesis.

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VITAMINS 1. Vitamin B12 (cyanocobalamin) must be taken for life IM for pernicious anemia. 2. Vitamin B6 (pyridoxine) is necessary for neurological transmission. 3. Vitamin C (ascorbic acid) is necessary to prevent scurvy and assist with wound healing.

FAT-SOLUBLE VITAMINS Nursing Implications 1. Fat-soluble vitamins A, D, E, and K are stored in the liver in large amounts. 2. Vitamin K is needed for the production of prothrombin. Vitamin K is formed by bacteria in the gastrointestinal tract. It is given to all newborn babies because the neonate has a sterile bowel and bacteria are necessary for the formation of vitamin K. It is also given before liver surgery because vitamin K is stored in the liver. 3. Vitamin D is necessary for the absorption of calcium. It is produced when the skin is exposed to sunlight. Milk is fortified with vitamin D.

◆ Fat-Soluble Vitamins Vitamin

Trade Name

Vitamin K Vitamin D Vitamin A Vitamin E

AquaMEPHYTON Calderol Alphalin Aquasol E

◆ Pancreatic Enzymes Generic Name

Trade Name

Pancrelipase Pancreatin Treatment:

Viokase, others No common trade name Pancreatic insufficiency is associated with chronic pancreatitis, pancreatomy, and cystic fibrosis. Replacement of pancreatic enzymes in clients with pancreatic insufficiency Diarrhea, nausea, stomach cramps, abdominal pain (high doses only), hematuria, rash, hives

Desired effect: Side effects:

Chapter

11

Ophthalmic Drugs

DRUGS USED FOR DISORDERS OF THE EYE 1. The term glaucoma refers to a group of diseases characterized by elevations of intraocular pressure (IOP). Increased IOP can cause damage to the optic nerve and blindness. 2. Glaucoma has two principal forms: open-angle glaucoma and closed-angle glaucoma. 3. In both forms, the cause of abnormally high IOP is impairment of aqueous humor outflow from the anterior chamber of the eye. 4. Open-angle glaucoma is by far the most common cause of increased IOP. 5. Approximately 90–95% of individuals with glaucoma have the open-angle form of the disease. 6. Open-angle glaucoma is a painless, insidious disease in which injury to the eye develops over a period of years. Symptoms are usually absent until extensive visual damage has been produced. 7. Open-angle glaucoma is usually bilateral and may progress insidiously to complete blindness without ever producing an acute attack. 8. There may be times when a person with chronic open-angle glaucoma notices a loss of peripheral vision or has foggy vision and diminished accommodation. Peripheral vision is gradually lost over a period of years and may be the first and only symptom the client experiences. 115

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◆ Chapter 11 9. The disease usually has a genetic basis and is most common in those over the age of 40. 10. Open-angle glaucoma is managed primarily by chronic drug therapy. 11. Drugs decrease IOP by either (1) promoting outflow of aqueous humor, or (2) decreasing aqueous humor production. 12. Acute angle-closure glaucoma is a medical emergency. The aim of treatment is to open the closed chamber angle and permit outflow of aqueous humor. While this goal may sometimes be achieved medically, surgery is usually eventually required. 13. Acute angle-closure glaucoma may produce symptoms in which the person experiences transitory attacks characterized by diminished visual acuity, colored halos around lights, and head and eye pain. These transitory attacks may last only a few hours, recurring at intervals of weeks or years before the person experiences full-blown prolonged attacks of acute glaucoma. 14. Urgent reduction of IOP is best accomplished by the use of hyperosmotic agents, including oral glycerin and sorbitol or IV mannitol. Laser surgery or surgical iridotomy is curative in most cases.

◆ Ophthalmic Agents to Decrease Production of Aqueous Humor Generic Name

Trade Name

Acetazolamide (carbonic anhydrase inhibitor) Levobunolol (beta blocker) Timolol (beta blocker) Betaxolol (beta blocker) Carteolol (beta blocker) Metoprolol (beta blocker) Major side effects:

Diamox

Treatment:

Betagan Timoptic, Blocadren Betoptic Cartrol Lopressor Diamox: hypotension, drowsiness, paresthesias; for beta blockers local effects are generally minimal, although clients commonly complain of transient ocular stinging; occasionally the beta blockers will cause conjunctivitis, blurred vision, photophobia, and dry eyes. Carbonic anhydrase inhibitors and beta blockers are used to treat glaucoma; they reduce intraocular pressure (IOP) in chronic open-angle glaucoma by decreasing the production of aqueous humor; beta blockers reduce production of aqueous humor by an unknown mechanism; the beta-adrenergic antagonists, timolol, betaxolol, carteolol, and metoprolol are first-line drugs for treatment of glaucoma because they cause less disturbance of vision than pilocarpine and other agents used to treat glaucoma.

Note: The effect of Diamox is due to inhibition of carbonic anhydrase activity in the proximal renal tubule, preventing formation of carbonic acid. Inhibition of carbonic anhydrase in the eye reduces the rate of aqueous humor formation, with consequent lowering of intraocular pressure.

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◆ Ophthalmic Agents to Increase Aqueous Outflow Generic Name

Trade Name

Physostigmine Pilocarpine Epinephrine Dipivefrin Treatment:

Antilirium Pilocar, others No common trade name Propine To reduce IOP in acute open-angle glaucoma and chronic closed-angle glaucoma by increasing aqueous humor outflow, especially after iridectomy for treatment of acute closed-angle glaucoma Physostigmine: bronchospasm, pulmonary edema, blurred vision, conjunctivitis, convulsions Pilocarpine: blurred vision, eye pain, bradycardia, bronchospasm, hypotension Epinephrine: eye pain, brow ache, blurred vision, tachycardia, elevation of blood pressure Propine: hypertension, tachycardia

Major side effects:

Note: Propine is converted to epinephrine by esterase in the eye, but unlike epinephrine, it produces only minimal systemic sympathomimetic effects.

◆ Ophthalmic Agents Used in Neonates Generic Name

Trade Name

Tetracycline suspension Erythromycin Use:

Cyclopar, others No common trade name The instillation of a prophylactic agent in the eyes of all neonates is mandatory in the United States as a precaution against ophthalmia neonatorum. Tetracycline: nausea, vomiting, diarrhea, photosensitivity Erythromycin: nausea, vomiting, diarrhea

Major side effects:

Chapter

12

Chemotherapy Used to Treat Infectious Diseases

CHEMOTHERAPY USING ANTI-INFECTIVES 1. Although we often think of chemotherapy as the use of drugs to kill or suppress cancer cells, this term was first defined as the use of chemicals against invading organisms (e.g., bacteria, viruses, fungi). Today, it is applied to the treatment of cancer as well as the treatment of infection. Hence, not only do we speak of cancer chemotherapy, we also speak of chemotherapy for infectious diseases. 2. It has become common practice to use the terms antibiotic and antimicrobial drug interchangeably. We will follow that practice here. However, the formal definitions of these words are not identical. Antibiotics are actually made by microorganisms; antimicrobial drugs are defined as any agent, natural or synthetic, that has the ability to kill or suppress microorganisms. From the perspective of therapeutics, there is no benefit to be gained from distinguishing between drugs made by microorganisms and drugs derived from other sources; hence the current practice of using the terms antibiotic and antimicrobial drug as synonyms. 3. The first rule of antimicrobial therapy is to match the drug with the organism. Therefore, whenever possible, the infecting organism should be identified prior to initiation of drug therapy. 4. The quickest, simplest technique for identifying microorganisms is microscopic examination of a gram-stained preparation. Samples for examination can be obtained from sputum, blood, urine, pus, and other body fluids. 118

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5. Because of the emergence of drug-resistant organisms, testing for drug sensitivity is common. However, sensitivity testing is only used when the infecting organism is one in which resistance is likely. For example, microbes such as group A streptococci have remained highly susceptible to penicillin; therefore, sensitivity testing is unnecessary. In contrast, when resistance is common, as it is with Staphylococcus aureus and the gram-negative bacilli, tests for drug sensitivity should be performed. 6. Use of all antimicrobial drugs promotes the emergence of drug-resistant organisms. However, some agents are more likely to promote resistance than others. Since broad-spectrum antibiotics kill more competing organisms than do narrowspectrum drugs, emergence of resistance is facilitated most by the broad-spectrum drugs. The more those antibiotics are used, the faster drug-resistant organisms will emerge. Not only do antibiotics promote emergence of resistant pathogens, these drugs also promote overgrowth of normal flora that possess mechanisms for resistance. 7. Since hospitals are sites of intensive antibiotic use, resident organisms can be extremely drug resistant. As a result, nosocomial infections (infections acquired in hospitals) are among the most difficult to treat. 8. Superinfections are simply an example of the emergence of drug resistance. A superinfection is defined as a new infection that appears during the course of treatment for a primary infection. A new infection can develop because antibiotic use can eliminate the inhibitory influence of normal flora, thereby allowing a second infectious agent to flourish. 9. Because broad-spectrum antibiotics kill more normal flora than do narrowspectrum drugs, superinfections are more likely to occur with use of broadspectrum agents. Superinfections can be difficult to treat, since they are, by definition, caused by microbes that are drug resistant.

NURSING IMPLICATIONS 1. Tetracycline can discolor developing teeth. Use of tetracycline should be avoided by pregnant women and children less than 8 years of age. Tetracycline can promote bacterial superinfections of the bowel, resulting in diarrhea. Instruct the patient to notify the physician if diarrhea develops. 2. Erythromycin is generally free of serious toxicity and is one of the safest antibiotics. It is often prescribed if the patient is allergic to penicillin. 3. Streptomycin may cause damage to the eighth cranial nerve, resulting in hearing loss. 4. The penicillins are nearly ideal antibiotics, and are active against a variety of bacteria. a. Allergic reactions constitute their principal adverse effect. b. Because of their safety and effectiveness, the penicillins are widely prescribed.

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5.

6.

7.

8. 9.

c. Instruct the patient to take oral penicillin with a full glass of water 1 hour before or 2 hours after meals. Penicillin V, amoxicillin, and bacampicillin may be taken with meals. Cephalosporins are bactericidal via inhibition of synthesis of bacterial cell walls. a. First-generation drugs include cefadroxil and cefazolin. Second-generation drugs include cefaclor and cefprozil. Third-generation drugs include cefixime and cefdinir. b. Major side effects include bone marrow suppression and decreased WBC count, platelets, and hematocrit. Other side effects include diarrhea, nausea, vomiting, superinfections, abdominal pain, rash, and fever. c. The nurse should culture infections per the doctor’s orders and arrange for sensitivity tests before beginning drug therapy as well as during therapy if the expected response is not seen. Administer antimicrobials with food to decrease GI upset and enhance absorption. Assess for signs of superinfections and discontinue the drug if a hypersensitivity reaction occurs. Aminoglycosides are bactericidal; they inhibit protein synthesis in susceptible strains of gram-negative bacteria by disrupting the functional integrity of the bacterial cell membrane. a. Representative drugs are neomycin (oral), streptomycin, and tobramycin (parenteral). b. Major side effects include ototoxicity, nephrotoxicity, hepatotoxicity, and hepatomegaly. c. The nurse should monitor the duration of treatment. The usual duration is 7–10 days. If no clinical response is seen within 3–5 days, stop therapy. Prolonged treatment leads to an increased risk of toxicity. If the drug is used longer than 10 days, monitor auditory and renal function daily. Ensure that the patient is well hydrated before and during therapy. Provide small and frequent meals if nausea or anorexia occur. Macrolides are bacteriostatic or bactericidal in susceptible bacteria. They bind to cell membranes and cause changes in protein function, leading to bacterial cell death. a. Representative drugs are azithromycin, clarithromycin, erythromycin, and dirithromycin. b. Major side effects include reversible hearing loss, uncontrollable emotions, abnormal thinking, abdominal cramping, anorexia, diarrhea, anaphylaxis, and superinfection. c. The nurse should culture sites of infection before therapy per the doctor’s orders. d. Administer erythromycin base or stearate on an empty stomach, 1 hour before or 2–3 hours after meals, with a full glass of water. Oral erythromycin estolate,

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ethylsuccinate, and certain enteric-coated tablets may be given with meals; always check the manufacturer’s instructions. e. Monitor liver function in patients on prolonged therapy. 10. Fluoroquinolones are bactericidal, interfering with DNA replication in susceptible gram-negative bacteria, preventing cell reproduction and leading to the death of the bacteria. a. Representative drugs include ciprofloxacin, levofloxacin, sparfloxacin, and lomefloxacin. b. Major side effects include headache, dizziness, insomnia, nausea, vomiting, photosensitivity, and elevated BUN, AST, ALT, and serum creatinine. c. The nurse should arrange for culture and sensitivity testing before beginning therapy per the doctor’s orders. d. Administer oral drug 1 hour before or 2 hours after meals with a glass of milk. Administer antacids, if needed, at least 2 hours after dosing aminoglycosides. e. Monitor clinical responses and if no improvement is seen or a relapse occurs, repeat culture and sensitivity tests. 11. Sulfonamides are bacteriostatic; they competitively antagonize paraaminobenzoic acid in susceptible gram-negative and gram-positive bacteria, causing cell death. a. Representative drugs include sulfadiazine, sulfamethizole, and sulfamethoxazole. b. Major side effects include glossitis, stomatitis, proctitis, nausea, diarrhea, vaginitis, and dermatitis. c. The nurse should arrange for culture and sensitivity tests of infected areas prior to therapy and repeat cultures if the response is not as expected. d. Ensure adequate fluid intake. Provide small frequent meals if GI upset occurs.

ANTIMICROBIAL DRUGS OF CHOICE ◆ Common First-Line Antimicrobials Organism

Drug of Choice

Penicillin-resistant Streptococcus and methicillin-resistant S. pneumococci Staphylococcus aureus Methicillin-resistant

Zyvox (linezolid)

Penicillin G or V Vancomycin with or without rifampin (continued)

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◆ Common First-Line Antimicrobials (continued) Organism

Drug of Choice

Gardnerella vaginalis Legionella pneumophila (Legionnaire’s disease) Pseudomonas aeruginosa (urinary tract infection) Mycobacterium tuberculosis

Metronidazole Erythromycin plus rifampin

Chlamydia trachomatis Rocky Mountain spotted fever Treponema pallidum (syphilis) Herpes simplex virus (genital) Treatment of lower respiratory tract infections and other acute bacterial exacerbations

Ciprofloxacin Isoniazid (INH) plus rifampin; pyrazinamide with or without ethambutol Tetracycline Tetracycline Penicillin G Acyclovir Zithromax (azithromycin)

Note: Only a few antimicrobial drugs used to destroy specific organisms are listed. There are many more organisms with a known drug of choice, but there is no reason for a nurse to know them all.

NURSING IMPLICATIONS 1. Antimicrobial therapy is assessed by monitoring clinical responses and laboratory results. The frequency of monitoring is directly proportional to the severity of infection. 2. Important clinical indicators of success are reduction of fever and resolution of signs and symptoms related to the affected organ system (e.g., improvement of breath sounds in patients with pneumonia). 3. Success of therapy is indicated by the disappearance of infectious organisms from post-treatment cultures; these cultures may become sterile within hours of the onset of treatment (as may happen with urinary tract infections), or they may not become sterile for weeks (as may happen with tuberculosis). 4. Assess the patient for allergic reactions to antimicrobials, especially during the first few days of drug therapy. The allergic reactions and side effects of the antiinfective the patient is receiving may cause signs and symptoms similar to those of the infection itself (e.g., nausea, vomiting, diarrhea, abdominal pain). The nurse should report any of these signs and symptoms after an anti-infective drug is given. 5. Check the patient’s history and laboratory data. Inquire about any previous infections that may have occurred (e.g., upper respiratory tract or lower urinary tract infections).

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6. Observe the patient for signs of nosocomial infections. 7. Evaluate the current status of the patient, including signs of renal failure, respiratory distress, circulatory congestion, and systemic infection. 8. Note the patient’s nutritional status and current eating habits. 9. Check the type and location of any pain. 10. Note the color, consistency, and amount of urine; antimicrobial therapy can be very damaging to the liver and renal system. 11. Encourage the adult patient to drink at least 1500–2000 mL of fluid every day; this will help flush the degraded antimicrobial out of the body.

DRUG THERAPY FOR URINARY TRACT INFECTIONS 1. Urinary tract infections (UTIs) are the most common infections encountered today. 2. UTIs may be classified according to their location, in either the lower urinary tract or the upper urinary tract. 3. Within this classification scheme, cystitis and urethritis are considered lower tract infections. 4. Pyelonephritis is considered an upper tract infection.

ACUTE CYSTITIS 1. Clinical manifestations are dysuria, urinary urgency, and urinary frequency. 2. Causative organisms are Escherichia coli (87%), Staphylococcus saprophyticus (11%), and Streptococcus faecalis (2%). 3. Antibiotics used to treat cystitis include cephalosporins or tetracycline. 4. Because cystitis causes urinary spasms, oxybutynin chloride (Ditropan) may be used as an antispasmodic agent, or for an overactive bladder (side effect: leukopenia). 5. Cystitis causes pain; therefore, urinary analgesics such as phenazopyridine (Pyridium) should be given. This agent will alleviate the pain and burning sensation that occurs during urination. Co-trimoxazole (Septra or Bactrim) may also be used. 6. Side effects of these drugs include thrombocytopenia, agranulocytosis, leukopenia, and hemolytic anemia. Pyridium turns urine red-orange.

URINARY TRACT ANTISEPTICS Urinary tract antiseptics are drugs for which use is restricted to the treatment of urinary tract infections (UTIs).

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◆ Urinary Tract Antiseptics Generic Name

Trade Name

Nitrofurantoin Methenamine Cinoxacin Desired effects:

Furadantin, Macrodantin Mandelamine, Urex Cinobac These urinary tract antiseptics are bacteriostatic in low concentrations, and interfere with bacterial carbohydrate metabolism; they are bactercidal in high concentrations, disrupting bacterial cell wall formation and causing cell death. Common side effects include nausea, vomiting, anorexia, and abdominal cramps. Urinary tract infections and prevention of urinary tract infections Teach patients to take the drug with food or milk; be sure that patients complete the full course of drug therapy to ensure resolution of the infection; take this drug at regular intervals around the clock; educate patients about side effects of the drug and be sure they report any side effects to their health care provider.

Major side effects: Treatment: Nursing implications:

DRUGS FOR SEXUALLY TRANSMITTED DISEASES CHLAMYDIAL INFECTION 1. Sexually transmitted diseases (STDs) are defined as infectious or parasitic diseases that are transmitted primarily through sexual contact. 2. Chlamydia trachomatis is the most common bacterial STD in the United States. 3. About 3 million new cases develop each year. The drug of choice is doxycycline (Vibramycin) or tetracycline (Achromycin) when allergic to penicillin. 4. The recommended first-line treatment for adults and adolescents who have chlamydial infections is drug therapy with tetracycline, erythromycin, or azithromycin. The drug of choice for C. trachomatis infection during pregnancy is erythromycin. a. Although the symptoms are mild and the infection is benign, it causes sterility in up to 50,000 women each year, primarily from fallopian tube scarring.

TRICHOMONIASIS 1. Trichomoniasis is caused by Trichomonas vaginalis. In women, the infection may be asymptomatic or may cause a thin, watery vaginal discharge along with burning and itching sensations. 2. In men, the infection is usually symptom free.

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3. Most infections can be eliminated with a single 2-gram dose of metronidazole (Flagyl).

GONOCOCCAL INFECTION 1. Gonorrhea is caused by Neisseria gonorrhoeae. 2. The incidence of gonorrhea is high: about 700,000 cases are reported annually. 3. In men, the main symptoms are a burning sensation while urinating and puslike discharge from the penis. 4. In contrast, gonorrhea in women is commonly asymptomatic. However, serious infection of female reproductive anatomy (vagina, urethra, cervix, ovaries, fallopian tubes) can occur, ultimately resulting in sterility. 5. The drug of choice for uncomplicated gonorrhea is ceftriaxone (Rocephin) administered in a single IM dose (125–250 mg). Other drugs such as penicillin PO are also effective but there may be an issue with compliance since it may be prescribed for as long as 10 days. Penicillin is less costly and compliance is not an issue with an injection.

PELVIC INFLAMMATORY DISEASE 1. Acute pelvic inflammatory disease (PID) is a syndrome that includes endometritis, pelvic peritonitis, ovarian abscess, and inflammation of the fallopian tubes. Infertility can result. 2. Prominent symptoms are abdominal pain, vaginal discharge, and fever. 3. Most frequently, PID is caused by N. gonorrhoeae and/or C. trachomatis. 4. Because multiple organisms are likely to be involved, drug therapy must provide broad coverage. 5. For the hospitalized client, treatment with IV doxycycline (Vibramycin) can be used in combination with either IV cefoxitin (Mefoxin) or IV cefotetan. 6. This IV therapy is followed by oral therapy with doxycycline (Vibramycin). The entire course takes 10–15 days.

SYPHILIS 1. Syphilis is caused by the spirochete Treponema pallidum. 2. The incidence of syphilis has increased steadily over the past decade. 3. T. pallidum has remained highly responsive to penicillin G, the drug of choice for treatment. 4. Early symptoms include a primary lesion, in which one or more chancres (small, fluid-filled lesions) erupt on the genitalia; others may erupt on the anus, fingers, lips, tongue, nipples, tonsils, or eyes. These chancres are usually painless and

126 ◆ Chapter 12 typically disappear after 3–6 weeks, even untreated. Lymph nodes may become swollen. Alopecia may occur with or without treatment and is usually temporary. a. Latent syphilis is characterized by an absence of clinical symptoms, but will have a reactive serologic test. Because infective mucocutaneous lesions may develop for up to 4 years postinfection, the early latent stage is considered contagious. Approximately two-thirds of patients remain asymptomatic in the late latent stage; the rest develop characteristic late-stage symptoms. b. Late syphilis is the final, destructive noninfectious stage of the disease. It has three subtypes, any or all of which may affect the patient: late benign syphilis, cardiovascular syphilis, and neurosyphilis. In late benign syphilis the typical lesion is called a gumma, and it develops on the skin, bone, mucous membranes, upper respiratory tract, liver, or stomach between 1 and 10 years after the initial infection. The typical lesion is a chronic, superficial nodule or deep, granulomatous lesion that is solitary, asymmetrical, painless, and indurated. Cardiovascular syphilis develops about 10 years after the initial infection in approximately 10% of patients with late untreated syphilis. It causes fibrosis of elastic tissue of the aorta and leads to aortitis, usually in the ascending and transverse section of the aortic arch. Cardiovascular syphilis may be asymptomatic or may cause aortic insufficiency or aneurysm. Finally, symptoms of neurosyphilis develop in about 8% of patients with late untreated syphilis, and appear from 5–35 years after infection. The clinical effects consist of meningitis and widespread central nervous system damage that may include general paresis, personality changes, and arm weakness. c. Confirmation of the diagnosis is done by identifying T. pallidum from a lesion by darkfield microscopic examination. This method is most effective when the lesion is moist. The fluorescent treponemal antibody absorption test identifies antigen of T. pallidum in tissue, ocular fluid, cerebrospinal fluid (CSF), tracheobronchial secretions, and exudates from lesions. This is the most sensitive test for detecting syphilis in all stages. Once reactive, it remains so permanently. 5. Infants exposed to T. pallidum in utero can be born with syphilis. 6. Signs of congenital syphilis include body sores, rhinitis, and severe tenderness over bones, as well as deafness.

Nursing Implications r Stress the importance of completing the full course of antibiotic therapy, even after symptoms subside.

r Check for a history of drug sensitivity before administering the first antibiotic dose. r In cardiovascular syphilis, check for signs of decreased cardiac output (decreased urine output, hypoxia, decreased sensorium) and pulmonary congestion.

r In neurosyphilis, regularly check the level of consciousness and monitor vital signs. r In late syphilis, provide symptomatic care during prolonged treatment. r Remind patients that safer sex practices and consistent condom use are important measures in syphilis prevention.

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r Be sure to report all cases of syphilis to local public health authorities. Urge the patient to inform their sex partners about the infection so that they can also receive treatment.

HERPES SIMPLEX GENITAL INFECTIONS 1. Symptoms of primary infection develop 6–8 days after contact. 2. In females, blisters or vesicles can appear on the labia, vagina, cervix, and foreskin of the clitoris. 3. In males, vesicles develop on the penis and occasionally on the testicles. 4. Painful urination and watery discharge can occur in both sexes. 5. Patients may experience systemic symptoms, such as fever, headache, myalgia, and tender, swollen lymph nodes in the affected region. 6. Within days, the original blisters can evolve into large, painful, ulcerlike sores. 7. Over the next 2–3 weeks, all symptoms resolve spontaneously. 8. The virus will remain present in a latent state and can cause recurrences. 9. Since there is no cure, symptoms may reoccur for life. 10. Fortunately, subsequent episodes usually become progressively shorter and less severe, and in some cases may cease entirely. 11. Transmission of genital herpes infection can occur during the symptomatic period and for 1 week thereafter. 12. Infected individuals should avoid sexual contact during this time. Use of a condom reduces the risk of transmission.

◆ Drugs Used to Treat Genital Herpes Generic Name

Trade Name

Acyclovir Valacyclovir Famciclovir sodium Treatment:

Zovirax Valtrex Famvir Genital herpes

Note: The medications above are antiviral medications used in the treatment of infection and prophylaxis for recurrent genital herpes infections. There is no cure for genital herpes.

ACQUIRED IMMUNODEFICIENCY SYNDROME 1. The acquired immunodeficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV). 2. Since its identification as a new disease in 1981, AIDS has become a worldwide epidemic, and millions of people are now infected.

128 ◆ Chapter 12 3. AIDS is transmitted sexually and by sharing infected needles. HIV is present in all body fluids of infected individuals. 4. Transmission can be via intimate contact with blood, semen, and vaginal secretions. 5. The disease can also be transmitted by an accidental needlestick. 6. It can be transmitted to the fetus by an infected mother. 7. HIV can damage many cell types, especially those of the immune and nervous systems. 8. By attacking cells of the nervous system, the virus can cause dementia and peripheral neuropathies. 9. By attacking the immune system, the virus can greatly compromise the ability to mount an immune response. As a result, the client develops opportunistic diseases. Drugs used to treat these AIDS-associated infections are summarized below. 10. Zidovudine (azidothymidine) has been the drug of choice for HIV-infected patients. Zidovudine, formerly known as AZT, is now most often referred to by its trade name (Retrovir). Retrovir is gradually being combined with other new antiviral drugs that have less serious side effects. These drugs, like Retrovir, suppress viral replication, but do not kill the virus. Accordingly, Retrovir does not offer a cure, but it can delay onset of symptoms, reduce severity of symptoms, and significantly prolong life. 11. Current medical management for AIDS primarily consists of treatment with a combination of antiviral drugs referred to as a cocktail. 12. The effectiveness of Retrovir therapy or that of any other antiviral drug decreases over time. Development of drug resistance is believed to cause the decrease in effectiveness. 13. Combination therapy (use of more than one drug alternatively or simultaneously) is becoming standard practice. Immune suppression occurs as a side effect of these drugs and predisposes the client to opportunistic diseases.

◆ Drugs Used to Treat the Acquired Immunodeficiency Syndrome Generic Name

Trade Name

Nucleoside reverse transcriptase inhibitors (NRTIs) Tenofovir (TDF) Viread Desired effect: Inhibits reverse transcriptase activity leading to a blocking of HIV reproduction Side effects: Severe hepatomegaly, lactic acidosis (sometimes severe), and anorexia Treatment: HIV infection in combination with other antiretroviral drugs (continued)

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◆ Drugs Used to Treat the Acquired Immunodeficiency Syndrome (continued) Generic Name

Trade Name

Tenofovir (continued) Nursing implications:

Viread Educate female patients to avoid pregnancy while taking this drug; do not take any other drugs, prescription or over-the-counter, without consulting your health care provider; report severe diarrhea, changes in color of stool or urine, rapid respirations Ziagen Used in combination with other anti-HIV drugs to reduce the viral load as much as possible and decrease the chance of further viral mutation Severe to fatal lactic acidosis, severe to fatal hepatomegaly Educate patients that this drug has been connected with severe hypersensitivity reactions, which usually occur early in the use of the drug; educate patients to keep list of hypersensitivity reactions readily available, to stop the drug if any of these effects occur, and to notify their health care provider. Videx, Videx EC Inhibits replication of HIV, leading to cell death Pancreatitis, hematopoietic depression, hepatotoxicity Arrange for lab tests (CBC, SMA-12) before and frequently during therapy; monitor for bone marrow depression; ensure that the patient swallows Videx EC whole (do not cut, chew, or crush); monitor patient for signs of pancreatitis, abdominal pain, elevated enzymes; if such signs are seen, stop drug and resume only if pancreatitis has been ruled out Epivir Reverse transcriptase inhibition via DNA viral termination and HIV polymerase Pancreatitis, hepatomegaly, pancreatitis, peripheral neuropathy Arrange to monitor hematologic indices and liver function every 2 weeks during therapy; severe hepatomegaly with steatosis has occurred. Zerit Antiretroviral drug that inhibits replication of some retroviruses Pancreatitis, hepatomegaly, severe anemia, lactic acidosis Take the drug every 12 hours; take the extended-release form once each day; this drug should be used during pregnancy only if the potential benefit justifies the potential risk Hivid Inhibits cell protein synthesis and leads to cell death without viral replication Severe hepatomegaly, pancreatitis, peripheral neuropathy Educate the patient to take the drug every 8 hours around the clock; use an alarm clock to wake up at night to take medication; rest periods during the day may be needed; arrange for frequent blood tests; results of blood counts may indicate that the dosage needs to be decreased or the drug discontinued temporarily (continued)

Abacavir (ABC) Desired effects: Side effects: Nursing implications:

Didanosine (ddI) Desired effects: Side effects: Nursing implications:

Lamivudine (3TC) Desired effects: Side effects: Nursing implications: Stavudine (d4T) Desired effects: Side effects: Nursing implications:

Zalcitabine (ddC) Desired effects: Side effects: Nursing implications:

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◆ Drugs Used to Treat the Acquired Immunodeficiency Syndrome (continued) Generic Name Zidovudine (AZT) Desired effects: Side effects:

Trade Name

Retrovir Inhibits HIV replication in both T cells and monocytes Agranulocytopenia, severe anemia requiring transfusions, dyspnea, fever, severe anemia, anorexia Treatment: HIV infection in combination with other antiretroviral drugs Nursing implications: Take the drug every 4 hours around the clock using an alarm clock to wake up at night to take medication; rest periods during the day may be needed; arrange for blood test; results of blood counts may indicate that the dosage needs to be decreased or the drug discontinued temporarily; report extreme fatigue, lethargy, severe nausea, difficulty breathing Emtricitabine (FTC) Emtriva Desired effects: Inhibits HIV replication via reverse transcriptase inhibition Side effects: Nausea, diarrhea, headache, rash, darkening of the skin of the palms and soles of the feet; hepatomegaly with steatosis sometimes seen; pancreatitis Treatment: HIV infection in combination with other antiretroviral drugs Nursing implications: Pancreatitis can be life threatening; monitor blood tests for pancreatitis and stop the drug and contact the physician if signs of pancreatitis are seen. Non-nucleotide reverse transcriptase inhibitors (NNRTIs) Delavirdine (DLV) Rescriptor Desired effects: Inhibitor of HIV reverse transcriptase; binds directly to HIV reverse transcriptase and blocks DNA-dependent and DNA-independent polymerase Major side effects: Increased liver enzymes, anorexia, malaise, diarrhea, headache, anemia, rash Efavirenz (EFV) Sustiva Desired effects: Shown to be effective in suppressing the HIV virus in adults and children Side effects: Dizziness, drowsiness, anorexia Nursing implications: Arrange to monitor hematologic indices every 2 weeks; ensure that the patient is taking this drug as part of a combination therapeutic regimen; monitor for signs of opportunistic infections that will need to be treated appropriately; establish safety precautions if CNS effects occur, which are especially likely during the first few days of treatment. Nevirapine (NVP) Viramune Desired effect: Blocks the action of reverse transcriptase Side effects: Liver dysfunction, infection, diarrhea Treatment: HIV infection in combination with other antiretroviral drugs Protease inhibitors (PIs) (continued)

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◆ Drugs Used to Treat the Acquired Immunodeficiency Syndrome (continued) Generic Name

Trade Name

Amprenavir (APV) Desired effects: Side effects: Nursing implications:

Agenerase Inhibits HIV infection in combination with other antiretroviral agents Hyperglycemia, hypertriglyceridemia, anorexia, peripheral paresthesias Do not take this drug with a high-fat meal and do not drink grapefruit juice while on this drug. Crixivan Inhibits HIV protease activity, leading to production of immature noninfective HIV particles Hyperbilirubinemia, hematuria, nocturia, headache, palpitations, diarrhea, dysuria, anorexia Take this drug on an empty stomach 1 hour before or 2 hours after a meal, with a full glass of water; if GI upset is severe, take with a light meal; avoid grapefruit juice and foods high in calories, fat, or protein; store capsules in the original container because they are very sensitive to moisture. Viracept Prevents viral cleavage, resulting in the production of immature noninfectious viruses Seizures, diarrhea, liver enzyme elevation, anorexia, diarrhea, dyspnea, sexual dysfunction Administer drug with a meal or a light snack; powder may be mixed with a small amount of non-acidic food or beverage; use within 6 hours of mixing; monitor patient for signs of opportunistic infections that will need to be treated appropriately. Norvir Inhibits HIV protease activity, leading to a decrease in production of HIV particles Anxiety, hematuria, apnea, anorexia, liver dysfunction, diarrhea Take the drug with meals or food; refrigerate capsules; the taste of the solution may improve if mixed with chocolate milk, Ensure, or Advera 1 hour before taking; do not drink grapefruit juice while using this drug. Invirase Protease inhibitor, which in combination with nucleoside analogues is effective in treating HIV infections with changes in surrogate markers Anorexia, insomnia, paresthesias, headache, elevated CPK, elevated triglycerides and cholesterol; fat redistribution may occur (central obesity, buffalo hump, cushingoid appearance) Fortovase Keeps infected cells from producing new mature viruses (continued)

Indinavir (IDV) Desired effects: Side effects: Nursing implications:

Nelfinavir (NFV) Desired effects: Major side effects: Nursing implications:

Ritonavir (RTV) Desired effects: Side effects: Nursing implications:

Saquinavir (SQV) Desired effects: Side effects:

Saquinavir (SQV) Desired effect:

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◆ Drugs Used to Treat the Acquired Immunodeficiency Syndrome (continued) Generic Name

Trade Name

Saquinavir (SQV) (continued) Side effects: Nursing implications:

Fortovase Headache, insomnia, malaise, dizziness, paresthesias, fatigue Take drug within 2 hours of a full meal; take concurrently with other prescribed medications; do not drink grapefruit juice while using this drug; store drug in refrigerator; use by expiration date Reyataz Keeps infected cells from producing new mature viruses Hyperbilirubinemia, prolonged PR interval; first-degree A-V block Take drug with food; take concurrently with other prescribed medications; take the drug 2 hours before or 1 hour after antacids or didanosine; swallow the capsules whole (do not chew or crush) Lexiva Keeps infected cells from producing new mature viruses Skin rash, GI intolerance, headache Take drug with or without food, but always with a full glass of water; take the drug 21 /2 hours before or after didanosine Kaletra Keeps infected cells from producing new mature viruses GI intolerance, headache, weakness, asthenia, increased liver function tests, pancreatitis Take drug with food; take concurrently with other prescribed medications; store capsules in the refrigerator

Atanzavir (ATV) Desired effect: Side effects: Nursing implications:

Fosamprenavir (f-APV) Desired effect: Side effects: Nursing implications: Lopinavir + ritonavir (LPV/r) Desired effect: Side effects: Nursing implications:

Note: Retrovir has the most serious side effects, which include anemia and neurotoxicity.

◆ Agents Used to Treat AIDS-Related Opportunistic Diseases Generic Name

Trade Name

Co-trimoxazole Pentamidine Sulfisoxazole Fluconazole Amphotericin B Interferon beta-1b

Bactrim, Septra No commonly used trade name Gantrisin Diflucan Fungizone Betaseron • Bactrim, Septra This drug should not be administered to patients with severe renal failure, hepatic disease, or hypersensitivity to sulfonamides; educate patients about its side effects, including anorexia, nausea, vomiting, fatigue, depression, stomatitis, depression, headache, vertigo, and photosensitivity.

Nursing implications:

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◆ Agents Used to Treat AIDS-Related Opportunistic Diseases (continued) Generic Name

Nursing implications:

Nursing implications:

Nursing implications:

Nursing implications:

Nursing implications:

Trade Name • Pentamidine This is used in the treatment (IM or IV) and prevention (inhalational) of Pneumocystis carinii pneumonia; inform patients of side effects, including tachycardia, hypotension and hypertension, syncope, shortness of breath, bronchospasm, and laryngospasm; have frequent blood tests and blood pressure checks, because this drug may cause many changes in the body. • Gantrisin Used for acute infections caused by susceptible organisms; it is CDC recommended for treatment of sexually transmitted diseases; it is also used for other diseases (e.g., UTIs, chancroid, inclusion conjunctivitis, trachoma, nocardiosis, toxoplasmosis); teach patients side effects of the drug, including headache, peripheral neuropathy, depression, photosensitivity, nausea, vomiting, crystalluria, hematuria, and agranulocytosis; teach patients to take the drug on an empty stomach, 1 hour before or 2 hours after meals, with a full glass of water; arrange for culture and sensitivity tests before therapy; repeat cultures if response is not as expected. • Fluconazole Used in the treatment of oropharyngeal, esophageal, vaginal, and systemic candidiasis, cryptococcal meningitis, and prophylaxis for candidiasis in bone marrow transplants; teach patient side effects of headache, nausea, vomiting, diarrhea, abdominal pain, and AST/ALT elevations; culture before therapy; begin treatment before lab results are returned; decrease dosage in cases of renal failure; infuse IV only; not intended for IM or subcutaneous injections • Amphotericin B This drug is reserved for patients with progressive, potentially fatal infections (e.g., cryptococcosis, cryptococcal meningitis); teach patient side effects of drug: fever (often with shaking chills), headache, generalized pain, hypokalemia, azotemia, hyposthenuria, renal tubular acidosis, nephrocalcinosis, normochromic normocytic anemia, pain at the injection site with phlebitis and thrombophlebitis; long-term use of this drug will be needed; beneficial effects may not be seen for several weeks; the systemic form of the drug can only be given IV; for topical application, apply liberally to affected area after first cleaning the area; educate patients to report pain or irritation at the injection site, GI upset, loss of appetite, difficulty breathing, and other side effects to health caregiver. Assess allergy to interferon beta or any component of the product. Obtain laboratory test (CBC, differential granulocytes and hairy cells, bone marrow hairy cells, and liver function tests) before therapy and monthly during therapy. Monitor for severe drug reactions; notify physician immediately; you may need to reduce dosage or discontinue drug. Ensure that patient is well hydrated, especially during initiation of treatment. Because depression is a side effect of this drug, monitor for mental disorder or suicidally tendencies. Drug should not be used in pregnancy. (continued)

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◆ Agents Used to Treat AIDS-Related Opportunistic Diseases (continued) Generic Name

Trade Name

Interferon beta-1b Nursing implications: for opportunistic diseases

Betaseron AIDS-related Kaposi’s sarcoma, metastatic renal carcinoma, malignant melanoma; teach patient side effects (e.g., hypocalcemia, leukopenia, neutropenia, thrombocytopenia, anemia, decreased hemoglobin, increased levels of AST, LDH, alkaline phosphatase, bilirubin, uric acid, serum creatinine, BUN, blood sugar, serum phosphorus; keep a chart of injection sites to prevent overuse of one area; arrange for proper disposal of needles and syringes; educate female patients to use contraceptives during drug therapy; teach patients to report side effects to their health caregiver and to use sunscreen and wear protective clothing if exposed to the sun because the drug makes the skin sensitive to the sun.

TUBERCULOSIS INFECTION 1. Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis, an organism also known as the tubercle bacillus. 2. Infections may be limited to the lungs or may be disseminated to other areas such as bone. 3. In the United States, approximately 10 million people harbor tubercle bacilli. 4. In most cases the bacteria are dormant and the infected individual is free of symptoms. 5. When the disease is active, morbidity can be significant; about 2000 Americans die from tuberculosis annually. 6. After years of being on the decline, the number of reported cases of tuberculosis is now increasing. 7. This increase is attributed to infection in people with AIDS and to the failure of clients with TB to complete their TB therapy, which should last from 9 months to a year. When a client with TB no longer has symptoms, he or she may believe that they are cured and discontinue drug therapy. This has caused mycobacteria to develop resistance to isoniazid.

CHEMOTHERAPY FOR ACTIVE TUBERCULOSIS 1. A variety of regimens have been employed to treat active tuberculosis. 2. Drug selection is based largely on drug susceptibility of the infecting organism and on the immunocompetence of the host. 3. Most regimens contain isoniazid (INH) plus rifampin. 4. Three modes are employed to evaluate therapy: chest x-ray, bacteriologic evaluation of sputum, and clinical evaluation.

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5. In order to eliminate tuberculosis, it is essential that individuals with asymptomatic infections are detected and treated. Detection is accomplished by screening. 6. It is recommended that all high-risk persons be screened. This group includes those with HIV infection, health care workers, and those with other risk factors for tuberculosis, such as chronic renal failure, hematologic malignancy, and use of immunosuppressive drugs. 7. The screen most often employed is the tuberculin skin test. The test is performed by giving an intradermal injection of a protein derived from mycobacteria. The protein is referred to as purified protein derivative (PPD; Mantoux test). The test is read 48–72 hours after injection. 8. In people harboring tubercle bacilli, injection of PPD can elicit a local hypersensitivity reaction. A positive reaction is indicated by the size of the zone of induration (hardness). 9. If an individual has a positive tuberculin skin test or clinical manifestations that suggest tuberculosis, diagnostic testing for tuberculosis should be done. A definitive diagnosis is made with microbiologic evaluation of sputum. 10. Because M. tuberculosis grows very slowly, results of sputum cultures are often delayed (by as long as 3–6 weeks). However, with newer culturing techniques, results can be obtained in less than 1 week. 11. The conventional culture method known as the acid-fast bacillus (AFB) test is less sensitive, but equivalent in specificity to, the newer polymerase chain reaction (PCR) test. PCR is a simple tool for amplifying a single nucleic acid sequence of DNA or RNA material to detect and identify the microorganism or gene in question. Detection of TB with PCR yields results in 1 day.

◆ Drugs Used to Treat Tuberculosis Generic Name

Trade Name

Tuberculostatic agents Isoniazid (INH) No common trade name Ethionamide Trecator-SC Pyrazinamide No commonly used trade Ethambutol HCl Myambutol Tuberculostatic and antibiotic agents Rifampin No commonly used trade name Rifapentine Priftin Cycloserine Seromycin Pulvules Capreomycin Capastat Sulfate Antibiotic agent (continued)

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◆ Drugs Used to Treat Tuberculosis (continued) Generic Name Trade Name Streptomycin Desired effect: Major side effects:

Treatment:

No commonly used trade name Antituberculostatic • Isoniazid: peripheral neuropathy, blood disorders, vitamin B6 deficiency, jaundice, fatal hepatitis • Trecator-SC: depression, drowsiness, peripheral neuritis, anorexia, nausea, vomiting, metallic taste, stomatitis • Pyrazinamide: thrombocytopenia, adverse effects on clotting and vascular integrity, hepatotoxicity, nausea, vomiting • Myambutol: Optic neuritis (loss of vision acuity change in color perception, fever malaise, headache, mental confusion disorientation, hallucination peripheral neuritis joint pain thrombocytopenia, and acute gout. • Rifampin: headache, drowsiness, fatigue, dizziness, rash, heartburn, epigastric distress, elevation of liver enzymes • Priftin: headache, dizziness, pyuria, proteinuria, hyperuricemia, liver enzyme elevation, nausea, vomiting, reddish discoloration of body fluids • Cycloserine: seizures, drowsiness, somnolence, headache, tremor, vertigo, confusion, rash, elevated serum transaminase levels • Capastat Sulfate: Tachycardia, angina pectoris, MI, Raynaud’s syndrome, CHF, hypotension renal insufficiency, renal failure, oliguria, urinary frequency, and thrombocytopenia. • Streptomycin: lethargy, confusion, depression, oliguria, nausea, vomiting, diarrhea, hepatotoxicity, renal toxicity, hematologic toxicity, glucose intolerance, azotemia, nephrotoxicity, blood disorders, eighth cranial nerve damage Antituberculostatic drugs used in the treatment of TB are divided into three categories: first-line drugs, second-line drugs, and third-line drugs; first-line drugs (isoniazid [INH], rifampin [RIF], ethambutol [EMB], pyrazinamide, Priftin) are considered more effective and less toxic than the second-line drugs; second-line drugs include cycloserine, Trecator-SC, and streptomycin; third-line drugs include capreomycin and ethionamide. Latent TB is usually treated with daily INH for 9 months. RIF daily for 4 months may be used for latent TB if bacteria show resistance to INH; for most adults with active TB, the recommended dosing includes the administration of four drugs daily for 2 months, followed by 4 months of INH and RIF. Drug therapy must be selected according to the patient’s condition and the organism’s susceptibility; second- and third-line drugs are reserved for drug-resistant strains; interruption of drug therapy may require initiation of therapy from the beginning of the regimen or additional treatment. Directly observed therapy (DOT) may be selected or required; in this type of therapy an assigned caregiver directly observes the administration of the drugs; the goal of DOT is to monitor the treatment regimen to assure compliance and to reduce the development of resistant organisms. Advise staff members and other persons who have been exposed to infected patients to receive tuberculin testing; chest x-rays and prophylactic INH may also be ordered; visitors and staff members should wear particulate respirator masks that fit closely around the nose and mouth when they are in the room with infected patients. (continued)

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◆ Drugs Used to Treat Tuberculosis (continued) Generic Name

Trade Name

Nursing implications:

Be alert for adverse effects of the medications; because INH use sometimes leads to hepatitis or peripheral neuritis, to prevent or treat peripheral neuritis give the patient pyridoxine (vitamin B6 ) as ordered.

AGENTS USED IN THE PREVENTION OF HEPATITIS B ◆ Drugs Used to Stimulate an Immunologic Response to Hepatitis and Haemophilus influenzae Generic Name

Trade Name

Hepatitis B vaccine Hepatitis A vaccine, inactivated Inactivated hepatitis A and hepatitis B recombinant vaccine Haemophilus b conjugate vaccine Haemophilus b conjugate vaccine with hepatitis B surface antigen (recombinant) Hepatitis B immune globulin (HBIG) Nursing implications:

Recombivax HB, Engerix-B Havrix, Vaqta Twinrix

Therapeutic effects:

Liquid PedvaxHIB Comvax

BayHep B, Nabi-HB There is no specific drug treatment for hepatitis, with the exception of hepatitis C, which has been treated somewhat successfully with alpha interferon; instead, patients are advised to rest in early stages of the illness and to combat anorexia by eating small, high-calorie, high-protein meals; protein intake should be reduced if signs or symptoms of pre-coma lethargy, confusion, and mental changes develop; provide rest periods throughout the day; schedule treatments and tests so the patient can rest between activities. Recombivax HB immunizes against infections caused by all known subtypes of hepatitis B virus, especially those seen in high-risk health caregivers, military personnel identified to be at risk, prisoners, users of illicit drugs, populations with a high incidence of TB (Eskimos, Indochinese refugees, Haitian refugees), morticians and embalmers, persons at risk because of their sexual practices, patients requiring frequent blood transfusions, residents in mental institutions, all infants, adolescents 11–12 years of age, and older unvaccinated adolescents at high risk. (continued)

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◆ Drugs Used to Stimulate an Immunologic Response to Hepatitis and Haemophilus influenzae (continued) Generic Name

Trade Name

Major side effects:

Malaise, fatigue, weakness, headache, soreness, erythema, tenderness, dizziness, low-grade fever, rhinitis, lymphadenopathy, hypotension, anaphylactic reaction Have epinephrine 1:1000 immediately available at the time of injection in case of severe anaphylactic reaction Inactivated hepatitis A vaccine (Havrix, Vaqta) contains hepatitis A antigen that stimulates production of specific antibodies against hepatitis A, which protects against HAV infection; the immunity does not protect against hepatitis caused by other agents. Inactivated hepatitis A and hepatitis B recombinant vaccine (Twinrix) provides inactivated hepatitis A antigens that stimulate production of specific antibodies against hepatitis A, which protect against hepatitis A, and inactivated hepatitis B surface antigen particles, which stimulate active immunity and production of antibodies against hepatitis B surface antigens. Haemophilus b conjugate vaccine (Liquid PedvaxHIB) provides immunization against Haemophilus influenzae type b, and stimulates an immunologic response in children, leading to active immunity against H. influenzae. Haemophilus b conjugate vaccine with hepatitis B surface antigen (Comvax) provides hepatitis B and Haemophilus type b vaccines to stimulate an immunologic response in children, leading to active immunity against these diseases. Hepatitis B immune globulin (HBIG) contains a high titer of antibody to hepatitis B surface antigen, providing passive immunity to hepatitis B.

Warning: Therapeutic effects:

ANTIFUNGAL AGENTS 1. Amphotericin B (Fungizone) is active against a broad spectrum of pathogenic fungi and is the drug of choice for most systemic mycoses (i.e., any disease induced by a fungus). 2. Amphotericin B is highly toxic; renal damage is a major concern. 3. For treatment of systemic mycoses, amphotericin B is almost always administered by IV infusion. 4. Ketoconazole (Nizoral) is an oral alternative to amphotericin B for treatment of less severe mycoses. This drug is less effective than amphotericin B, and has the additional advantage of being available in an oral form. 5. Ketoconazole is also active against superficial Candida infections. 6. Responses to ketoconazole are slow.

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◆ Drugs for Mycoses Generic Name

Trade Name

Amphotericin B Ketoconazole Nystatin Miconazole nitrate

Fungizone Nizoral Mycostatin Monistat 3, Monistat 7 (vaginal suppositories, topical) • Amphotericin B Amphotericin B is reserved for patients with progressive, potentially fatal infections, such as cryptococcosis, North American blastomycosis, disseminated moniliasis, and coccidioidomycosis, and infections by Mucor, Rhizopus, Absidia, Entomophthorales, Basidiobolus, sporotrichosis, and Aspergillus; it is also useful in treating cryptococcal meningitis in HIV-infected patients, and treatment of any kind of progressive fungal infection that does not respond to other treatment. Fever (often with shaking chills), headache, malaise, general pain, nausea, vomiting, normochromic normocytic anemia, renal failure, hypokalemia, azotemia, hyposthenuria, tubular acidosis, nephrocalcinosis • Mycostatin Oral: oropharyngeal candidiasis Vaginal: local treatment of vaginal candidiasis (moniliasis) Topical: treatment of cutaneous or mucocutaneous mycotic infections caused by Candida albicans and other Candida species Nausea, vomiting, vaginal irritation, vulvovaginal burning, local irritation • Ketoconazole Ketoconazole is active against the fungi that cause superficial infections caused by Candida species; Nizoral is an oral alternative to amphotericin B for treatment of less severe systemic mycoses; this drug is less effective than amphotericin B and responses to ketoconazole are slow. Ketoconazole: hepatotoxicity, rash, itching, fever, chills, diarrhea Monistat 3 Monistat 7 Vaginal suppositories: Local treatment of vulvovaginal candidiasis (moniliasis) Topical administration: Tinea pedis, tinea cruris, tinea corporis caused by Trichophyton rubrum, Trichophyton mentagrophytes, cutaneous candidias (moniliasis), tinea versicolor. Vaginal suppositories: irritation, sensitization or vulvovaginal burning, pelvic cramps Others: Rash, headache; Topical application: Irritation, burning maceration, allergic contact dermatitis

Treatment:

Major side effects:

Treatment:

Major side effects: Treatment:

Major side effects:

Treatment:

Major side effect:

Note: Nystatin is safer than amphotericin B and has the additional advantage of being orally available.

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ANTIVIRAL AGENTS 1. Several antiviral agents are approved for use in the United States. 2. These drugs are active against a narrow spectrum of viruses and their clinical applications are limited to specific viral infections. 3. Acyclovir (Zovirax) is the agent of first choice for infections caused by herpes simplex viruses, varicella zoster virus, and cytomegalovirus. 4. Acyclovir can be administered orally, intravenously, or topically. 5. Serious side effects are uncommon. 6. Zidovudine (Retrovir), formerly called azidothymidine (AZT), is used with other antiviral drugs to treat clients infected with the human immunodeficiency virus (HIV), the causative agent of acquired immunodeficiency syndrome (AIDS). a. Retrovir inhibits HIV replication by suppressing synthesis of viral DNA. 7. Didanosine (Videx), also known as dideoxyinosine or ddI, is approved for clients with advanced HIV infection who cannot tolerate zidovudine (Retrovir), or have experienced significant deterioration despite zidovudine therapy. 8. Zalcitabine (Hivid), also known as dideoxycytidine or ddC, is approved for combined use with zidovudine and other antiviral drugs to treat clients with advanced HIV infection. 9. Ganciclovir (Cytovene) is a synthetic antiviral agent with activity against herpes viruses, including cytomegalovirus.

◆ Antiviral Agents Generic Name

Trade Name

Acyclovir Zidovudine Didanosine Zalcitabine Ganciclovir Valacyclovir Ribavirin Treatment:

Zovirax Retrovir (formerly called AZT) Videx (also known as dideoxyinosine, ddI) Hivid (also known as dideoxycytidine, ddC) Cytovene Valtrex Virazole • Acyclovir: herpes simplex and varicella zoster virus (chickenpox) • Retrovir: HIV (AIDS) • Videx: HIV (AIDS) • Hivid: HIV (AIDS) • Cytovene: cytomegalovirus • Valtrex: Herpes zoster (shingles); genital herpes in HIV patients, & cold sores (herpes labialis) • Virazole: Respiratory syncytial virus infection (RSV), influenza virus

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◆ Antiviral Agents (Continued) Generic Name

Trade Name

Side effects:

Acyclovir: generally well tolerated; the most common side effects are phlebitis and inflammation at the infusion site and reversible nephrotoxicity. • Retrovir: severe anemia and granulocytopenia (abnormal reduction in granular leukocytes) are the principal toxic effects. • Videx: pancreatitis and bone marrow depression which can be fatal • Hivid: the major toxicities are peripheral neuropathy and less commonly pancreatitis. • Cytovene: the adverse effect of greatest concern is bone marrow suppression, which results in granulocytopenia (40%) and thrombocytopenia (20%). • Valtrex Adverse effect: Herpes zoster (shingles) and cold sores (herpes labialis) and herpes • Virazole Adverse effects: Depression, suicidal behavior, cardiac arrests, pneumothorax, bacterial pneumonia, hypotension, deteriorating respiratory function.

PROTOZOAL INFECTIONS 1. Pneumocystis carinii pneumonia is caused by Pneumocystis carinii; its classification is as both a protozoa and a fungus. 2. The incidence of Pneumocystis carinii pneumonia is extremely high (80%) in clients with AIDS. 3. The treatment of choice for clients who are severely immunocompromised is pentamidine. 4. The treatment of choice for other clients is trimethoprim (Proloprim) plus sulfamethoxazole (Gantanol). 5. Toxoplasmosis is caused by infection with Toxoplasma gondii, a protozoan. a. The parasite is harbored by many animals as well as by humans. b. Infection is acquired most commonly by eating undercooked meat or from contaminated feces from infected cats. Toxoplasmosis may also be congenital. c. The treatment of choice is pyrimethamine (Daraprim) combined with a sulfonamide. 6. Trichomoniasis is caused by Trichomonas vaginalis, a protozoan. a. Trichomoniasis is a common disease, affecting about 200 million people worldwide. b. The usual site of infection is the genitourinary tract. Parasites may also inhabit the rectum. c. In females, infection results in vaginitis.

142 ◆ Chapter 12 d. In males, infection results in urethritis. e. The disease is usually transmitted sexually, but can also be acquired by contact with contaminated objects (e.g., toilet seats). f. Treatment of choice is metronidazole (Flagyl).

ECTOPARASITICIDES 1. Ectoparasites are parasites that live on the surface of the host. 2. Most ectoparasites that infest humans live on the skin and hair. 3. Some live on clothing and bedding, moving to the host only to feed. 4. The principal ectoparasites that infest humans are mites and lice. 5. Infestation with lice is known as pediculosis. 6. Infestation with mites is known as scabies. 7. Both conditions produce intense pruritus (itching). 8. Infestations with mites and with lice can be eradicated with topical drugs.

SCABIES 1. Scabies are caused by infestation with Sarcoptes scabiei, an organism known commonly as the itch mite. 2. Irritation occurs as a result of the female mite burrowing beneath the skin to lay eggs. 3. The drug of choice to kill mites is permethrin (Elimite) (5% cream formulation). Lindane (G-Well) is also used to kill mites.

PEDICULOSIS 1. Pediculosis is a general term referring to infection with any of several kinds of lice. 2. The type of lice encountered most frequently are Pediculus humanus capitis (head louse) and Pthirus pubis (pubic or crab louse).

Pubic Lice 1. Pubic lice, commonly known as crabs, usually reside on the skin and hair of the pubic region. 2. Crabs are most common among people who have multiple sexual partners. 3. The treatment of choice is lindane (G-Well) and malathion (0.5% Prioderm lotion).

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Head Lice 1. Head lice reside on the scalp and lay their nits (eggs) on the hair shafts. 2. Head lice may be transmitted by close personal contact and by contact with infested clothing, hairbrushes, and other objects. 3. The drug of choice is benzene hexachloride, which is toxic to mites, lice, and their ova. Other drugs used are: a. Malathion (0.5% Prioderm lotion) kills head lice and ova. Note that this drug is flammable; a hair dryer cannot be used and the client should not smoke while applying the drug to wet hair. b. Lindane (G-Well) is considered both a scabicide and a pediculicide because it is effective in the treatment of both lice and mite infestations. It is available in 1% cream, lotion, and shampoo.

Chapter

13

Anticancer Drugs

1. Anticancer drugs are toxic to normal tissues, especially to tissue that has a high percentage of proliferating cells (e.g., bone marrow, hair follicles, gastrointestinal epithelium, germinal cells). 2. The three major modalities for treating cancer are surgery, radiotherapy, and chemotherapy (drug therapy). 3. Surgery and/or irradiation are preferred for most solid cancers. 4. Drug therapy is the treatment of choice for disseminated cancers (leukemias) and widespread metastases. 5. Drug therapy is also used as an adjunct to surgery and irradiation by killing malignant cells that surgery and irradiation leave behind. Adjuvant cancer chemotherapy can significantly prolong life. 6. Cancers with a high cure rate include Hodgkin’s disease, Ewing’s sarcoma, and acute lymphocytic leukemia. 7. At this time, the major impediment to successful chemotherapy is toxicity of anticancer drugs to normal tissue. 8. Researchers have created a cancer “smart bomb” that attacks and kills leukemia cells in mice without harming normal cells. Dr. F.M. Uckum of the University of Minnesota–Minneapolis reported that the “smart bomb” is actually an antibody that will attach to a receptor molecule found only on the surface of leukemia cells. “The antibody is the missile,” said Uckum, “and hooked to the missile is the payload—a chemical that actually kills the leukemia cell. Normal tissue is not affected; only the leukemia cells are going to die.” Uckum, the first author of a study appearing in the Journal of Science, March 1995, wrote that his team is beginning laboratory tests of the “smart bomb” technique against breast and ovarian cancers, but results are still years away. “There are certain substances in 144

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breast cancer that you can target,” he said. “If you do the targeting right, you can kill the breast cancer cells without killing normal cells.” 9. Characteristics of neoplastic cells (cancer cells) are unrestrained growth and division. The capacity for persistent proliferation is the most distinguishing property of malignant cells. 10. In the absence of intervention, cancerous tissues will continue to grow until they cause death. Malignant cells are unresponsive to the feedback mechanisms that regulate cellular proliferation in healthy tissue. 11. Metastases are secondary tumors that appear at sites distant from the primary tumor. Metastases result from the unique ability of malignant cells to break away from their site of origin, migrate to other parts of the body (via the lymphatic and circulatory system), and then reimplant to form a new cancerous tumor. 12. The abnormal behavior of cancer cells results from alterations in their DNA. These genetic alterations are caused by chemical carcinogens, viruses, and radiation (x-ray, radioisotopes, ultraviolet light). 13. Early detection of cancer is rare; at this time cancer of the cervix, which can be diagnosed with a Pap smear and is confirmed by biopsy, is the only neoplastic disease capable of truly early diagnosis. All other cancers are significantly advanced by the time they have grown large enough for discovery. 14. During the course of chemotherapy, cancer cells can develop resistance to the drugs used against them. 15. Use of anticancer agents favors the growth of drug-resistant cells; as therapy proceeds, the number of resistant cells will increase. 16. Because resistant cells cannot be killed with drugs, the risk of therapeutic failure increases with each course of therapy. 17. Since patients are usually exposed to drug therapy over an extended period, therapeutic failure owing to drug resistance is a significant problem. 18. The anticancer drugs fall into two major classes: cytotoxic agents and hormones and hormone antagonists.

◆ Anticancer Drugs: Cytotoxic Agents Generic Name Alkylating nitrogen mustards Cyclophosphamide Mechlorethamine Alkylating nitrosoureas Carmustine Streptozocin Alkylating platinum Cisplatin

Trade Name

Cytoxan Mustargen BiCNU Zanosar • Platinol

146 ◆ Chapter 13

◆ Anticancer Drugs: Cytotoxic Agents (continued) Generic Name Antimetabolite Methotrexate Pyrimidine analogue Cytarabine Fluorouracil Purine analogues Mercaptopurine Pentostatin Antitumor antibiotics Doxorubicin Mitoxantrone Plicamycin Mitotic inhibitors Vinblastine Vincristine Miscellaneous Asparaginase Hydroxyurea Procarbazine Treatment: Major side effects:

Nursing implications:

Trade Name

Folex Cytosar-U • Adrucil Purinethol Nipent Adriamycin Novantrone Mithracin Velban Oncovin • Elspar • Hydrea • Matulane Cancer Marrow depression, neutropenia (a severe reduction in white blood cell count), and a reduction in platelet count; infections secondary to neutropenia are the most serious complications of cancer chemotherapy; with most anticancer drugs onset of neutropenia is rapid; a normal white cell count ranges from 2500–7000/mm3 ; if neutropenia is substantial (absolute neutrophil count below 500/mm3 ), the next round of chemotherapy should be delayed until neutrophil counts return to normal; a neutrophil is a leukocyte that stains easily with neutral dyes; when bone marrow is depressed, decreased WBC count (leukocytopenia), decreased RBC count (anemia), and decreased platelet count (thrombocytopenia) have occurred. Arrange for blood and urine tests to evaluate renal function before therapy and weekly during therapy; monitor liver function tests and CBC; reduce or discontinue if renal toxicity occurs (proteinuria, elevated BUN, plasma creatine, serum electrolytes); use special caution when handling cytotoxic agents; contact with skin poses a carcinogenic hazard to the area exposed; wear rubber gloves; if powder or solution comes into contact with the skin, wash immediately with soap and water; arrange for pretherapy with an antiemetic if needed to decrease the severity of nausea and vomiting; monitor urine output frequently for any signs of renal failure.

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HORMONES AND HORMONE ANTAGONISTS 1. The hormones and hormone antagonists are the least toxic of all anticancer drugs. Because these agents act through specific hormone receptors on target tissue, their effects are relatively selective. As a result, these drugs are generally devoid of the severe toxicities that characterize most anticancer agents. 2. The hormonal anticancer drugs fall into five basic categories: (1) androgens and antiandrogens, (2) estrogens and antiestrogens, (3) progestins, (4) gonadotropinreleasing hormone (GnRH) analogues, and (5) glucocorticoids. 3. The principal indications for these drugs are cancer of the breast, endometrium, and prostate. 4. The glucocorticoids are also used against lymphomas and certain leukemias.

◆ Anticancer Drugs: Hormones and Hormone Antagonists Generic Name Androgens Fluoxymesterone Testosterone Antiandrogens Flutamide Estrogens Diethylstilbestrol Ethinyl estradiol Estrogen mustards Estramustine Tamoxifen Progestin Medroxyprogesterone GnRH analogues Goserelin Glucocorticoid Prednisone Major side effects:

Trade Name

Indications

Halotestin No commonly used trade name

Breast cancer Breast cancer

Eulexin

Metastatic prostate cancer

• Stilphostrol • Estinyl

Prostate and breast cancer Prostate and breast cancer

• Emcyt Nolvadex

Prostate cancer Breast cancer

Depo-Provera

Endometrial cancer

Zoladex

Prostate cancer

Deltasone

Acute and chronic lymphocytic leukemias, Hodgkin’s and non-Hodgkin’s lymphomas Antiandrogen: gynecomania (abnormal sex drive in the male); toxic hepatitis has occurred that has been fatal to patients. Estrogen: fluid retention, hypercalcemia, depression, thromboembolic disorders; gynecomastia may occur in males.

148 ◆ Chapter 13

◆ Anticancer Drugs: Hormones and Hormone Antagonists (continued) Generic Name

Trade Name

Major side effects: (continued)

Indications Estrogen mustard: thrombosis resulting in myocardial infarction (MI) or stroke, fluid retention, hypercalcemia Antiestrogen: Nausea, vomiting, hot flashes, menstrual irregularities Progestins: fluid retention and hypercalcemia; progestins are teratogens and should be avoided in the first 4 months of pregnancy. Gonadotropin-releasing hormone analogues: bone pain and urinary obstruction Glucocorticoids: adrenal insufficiency, increased susceptibility to infection, peptic ulcers, fluid and electrolyte disturbances, osteoporosis, growth retardation in children

Note: Side effects of androgens include clitoral enlargement, proliferation of facial and body hair, deepening of the voice, and increased libido.

BIOLOGICAL RESPONSE MODIFIERS 1. Biologic response modifiers are drugs that alter responses to cancer. 2. Many of these drugs are immunostimulants that enhance host defenses against cancer. 3. Some of these drugs render cancer cells nonmalignant by causing them to differentiate into nonproliferative forms. Some enable the host to better tolerate the myelosuppressive actions of anticancer drugs.

◆ Anticancer Drugs: Biologic Response Modifiers Generic Name Androgens Interferon alfa-2a Interferon alfa-2b Aldesleukin Interleukin-2 Levamisole

Trade Name

Indications

Roferon- A Intron A Proleukin

Hairy cell leukemia Kaposi’s sarcoma Metastatic renal cancer

Ergamisol

Stage II colon cancer (combination therapy with fluorouracil) (continued)

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◆ Anticancer Drugs: Biologic Response Modifiers (continued) Colony-stimulating factor

Generic Name

Trade Name

Filgrastim Desired effects:

Neupogen Increase the production of neutrophils (white blood cells) within the bone marrow Human granulocyte colony-stimulating factor is produced by recombinant DNA technology; increases the production of neutrophils within the bone marrow with little effect on the production of other hematopoietic cells Decreases the incidence of infection in patients with neutrophils (leukocytes that stain easily with dye); malignancies in patients receiving myelosuppressive anticancer drugs are associated with a significant incidence of severe neutropenia with fever; Neupogen helps reduce the duration of neutropenia following bone marrow transplant. Headache, fever, generalized weakness, fatigue, alopecia (absence or loss of hair, especially on the head), rash, mucositis (inflammation of mucous membranes), nausea, vomiting, anorexia, diarrhea, constipation, bone pain. Obtain CBC and platelet count prior to and twice weekly during therapy; doses may be increased after chemotherapy cycles according to the duration and severity of bone marrow suppression; do not give within 24 hours before or after chemotherapy; give daily for up to 2 weeks until the neutrophil count is 10,000/mm3 ; discontinue therapy if this number is exceeded; store drug in refrigerator; do not shake vial; each vial can be used only once; do not reuse syringes or needles (a proper container for disposal will be provided); for home situations, another person should be instructed in the proper administration technique; use sterile technique; Neupogen can be administered IV or SC.

Therapeutic actions:

Treatment:

Major side effects:

Nursing implications:

Chapter

14

Immunosuppressive Drugs

IMMUNOSUPPRESSIVE DRUGS 1. Immunosuppressive drugs inhibit immune responses. 2. These agents have two principal applications: (1) prevention of organ rejection (e.g., liver transplant) or suppression of allograft rejection (transplant of skin from the same species), and (2) treatment of autoimmune disorders (e.g., systemic lupus erythematosus, rheumatoid arthritis). 3. Two toxicities are of particular concern when immunosuppressive drugs are administered: increased risk of infection and increased risk of neoplasms. 4. Cyclosporine (Sandimmune) is the most effective immunosuppressant available, and is the drug of choice for preventing organ rejection. 5. Oral administration is preferred; intravenous administration is reserved for clients who cannot take the drug orally. 6. Cyclosporine increases the risk of infection, although less than the cytotoxic immunosuppressants.

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◆ Immunosuppressive Drugs Generic Name Helper T cell depressant Cyclosporine Glucocorticoids Methylprednisolone sodium succinate Prednisone Hydrocortisone Dexamethasone Cortisone acetate Fludrocortisone Cytotoxic drugs Cyclophosphamide Methotrexate Antibodies Antithymocyte globulin, equine Rho(D) immune globulin Treatment: Side effects:

Trade Name

Sandimmune Solu-Medrol, Medrol • Apo-Prednisone Cortef, Hydrocortone Decadron Cortone Acetate Florinef Acetate Cytoxan • Amethopterin No commonly used trade name RhoGAM Prevention of organ transplant rejection; treatment of autoimmune disorders Cyclosporine: nephrotoxicity, infection, hypertension Glucocorticoids: depression, euphoria, hypertension, decreased wound healing, adrenal suppression Cytotoxic drugs: bone marrow depression (myelosuppression) Antibodies: reactions are uncommon and mild

Chapter

15

Drug Therapy for Osteoporosis

Osteoporosis is a metabolic bone disorder in which the rate of bone resorption accelerates while the rate of bone formation slows down, causing a loss of bone mass. Bones affected by this disease lose calcium and phosphate salts and thus become porous, brittle, and abnormally vulnerable to fracture. Osteoporosis may be primary or secondary to an underlying disease. Primary osteoporosis is often called senile or postmenopausal osteoporosis because it most commonly develops in elderly postmenopausal women.

◆ Bisphosphonates (Calcium Regulators) Generic Name

Trade Name

Alendronate sodium Etidronate disodium Zoledronic acid Pamidronate disodium Risedronate sodium Desired effects:

Fosamax Didronel, Didronel IV Zometa Aredia Actonel Bisphosphonates inhibit bone resorption by inhibiting osteoclast activity and promoting osteoclast cell apoptosis (disintegration of cells into membrane-bound particles that are then phagocytosed by other cells); this action leads to decreased release of calcium from bone and decreased serum calcium level (continued)

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◆ Bisphosphonates (Calcium Regulators) (continued) Generic Name

Trade Name

Risedronate (continued) Side effects:

Actonel (continued) Fosamax: headache, dizziness, hypertension, chest pain, nausea, diarrhea, altered taste, metallic taste, abdominal pain, anorexia, esophageal erosion, elevated BUN and serum creatinine, hypokalemia, hypocalcemia, dyspnea, coughing, pleural effusions, increased or recurrent bone pain Bisphosphonates are used for treatment of osteoporosis (oral) in postmenopausal females and in males; hypercalcemic malignant tumors in patients who cannot be adequately managed by diet or oral hydration (parenteral); Paget’s disease of bone (oral) Administer Fosamax with a full glass of water 2 hours before meals or any other medication; make sure the patient stays upright for at least 30 minutes after administration; make sure that all patients taking bisphosphonates are well hydrated before and during therapy with parenteral agents; monitor serum calcium levels before, during, and after therapy; ensure adequate vitamin D and calcium intake; provide comfort measures if bone pain returns. Allergy to bisphosphonates, hypocalcemia, pregnancy, lactation, severe renal impairment; use cautiously in the presence of renal dysfunction or upper GI disease

Treatment:

Nursing implications:

Contraindications and cautions:

◆ Estrogen Receptor Modulator Generic Name

Trade Name

Raloxifene HCl Desired effects:

Evista Evista increases bone mineral density without stimulating the endometrium in women and modulates the effects of endogenous estrogen at specific receptor sites. Depression, lightheadedness, dizziness, headache, corneal opacities, decreased visual acuity, retinopathy, venous thromboembolism, severe itching of external female genitalia, vaginal bleeding, vaginal discharge, peripheral edema Prevention and treatment of osteoporosis in postmenopausal women Administer daily without regard to food and arrange for periodic blood counts during therapy; monitor patients for possible long-term effects, including cancers and thromboses associated with other drugs in this class; counsel patients about the need to use contraceptive measures to avoid pregnancy while taking this drug; inform patients that serious fetal harm could occur; assess patients for history of allergy to Evista, pregnancy, lactation, smoking, venous thrombosis

Side effects:

Treatment: Nursing implications:

154 ◆ Chapter 15

◆ Hormonal Agent Generic Name

Trade Name

Calcitonin (human), calcitonin (salmon) Desired effects:

Calcimar, Cibacalcin, Miacalcin Nasal Spray

Treatment:

Side effects:

The calcitonins are polypeptide hormones secreted by the thyroid; human calcitonin is a synthetic product classified as an orphan drug; salmon calcitonin appears to be a chemically identical polypeptide, but with greater potency per milligram and longer duration; both inhibit bone resorption, lower elevated serum calcium, and increase the excretion of filtered phosphate, calcium, and sodium by the kidney. Postmenopausal osteoporosis in conjunction with adequate calcium and vitamin D intake to prevent loss of bone mass (salmon calcitonin); emergency treatment for hypercalcemia (salmon calcitonin); Paget’s disease (human and salmon calcitonin); Paget’s disease is characterized by excessive bone resorption followed by abnormal bone formation. Salmon calcitonin: local inflammatory reactions at injection site and nasal irritation (nasal spray); human calcitonin: urinary frequency

NURSING IMPLICATIONS 1. These drugs can be given SC or IM; the patient or a significant other must learn how to do this at home. Refrigerate the drug vials. For intranasal use, alternate nostrils daily; notify health care provider if significant nasal irritation occurs. 2. Give skin test to patients with any history of allergies; salmon calcitonin is a protein, and risk of allergy is significant. 3. Refrigerate nasal spray until activated, then store at room temperature. 4. Use reconstituted human calcitonin within 6 hours. 5. Maintain parenteral calcium on standby in case of development of hypocalcemic tetany. 6. Monitor serum alkaline phosphatase and urinary hydroxyproline excretion prior to therapy and during the first 3 months, then every 3–6 months during long-term therapy. 7. Salmon calcitonin is contraindicated with allergy to salmon calcitonin or fish products, and during lactation. Use cautiously with renal insufficiency, osteoporosis, or pernicious anemia.

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DRUGS FOR BENIGN PROSTATIC HYPERPLASIA ◆ Alpha-Adrenergic Blockers Generic Name

Trade Name

Tamsulosin Prazosin Terazosin Doxazosin mesylate Desired effects:

Flomax Minipress Hytrin Cardura Alpha-adrenergic blockers relieve symptoms of benign prostatic hyperplasia (BPH) and decrease blood pressure in patients with hypertension. Headache, fatigue, dizziness, lethargy, vertigo, rhinitis, asthenia, anxiety, paresthesias, increased sweating, muscle cramps, insomnia, eye pain, conjunctivitis, tachycardia, palpitations, edema, orthostatic hypotension, chest pain, sexual dysfunction, increased urinary frequency Monitor for orthostatic hypotension, which is most marked in the morning and is accentuated by hot weather and alcohol; sodium and water retention, increased plasma volume, edema, dyspnea, syncope Name confusion has occurred between Fosamax (alendronate) and Flomax (tamsulosin); use caution

Side effects:

Nursing implications:

Clinical alert:

◆ Androgen Hormone Inhibitors Generic Name

Trade Name

Finasteride Doxazosin mesylate Desired effect: Side effects: Treatment:

Propecia, Proscar Cardura These relieve symptoms of benign prostatic hyperplasia (BPH). GI distress, impotence, decreased libido, decreased volume of ejaculation Proscar and Cardura are used for the treatment for symptomatic benign prostatic hyperplasia (BPH); most effective with long-term use; reduce the need for prostate surgery Administer Proscar and Cardura without regard to meals; protect container from light; arrange for regular follow-up, including prostate exam, PSA levels, evaluation of urine flow and liver and kidney function; monitor urine flow and output; an increase in urine flow may not occur; do not allow pregnant women to handle crushed or broken tablets because of risk of inadvertent absorption, adversely affecting the fetus; alert patients that libido may be decreased as well as the volume of ejaculate; these effects are usually reversible when the drug is stopped.

Nursing implications:

Chapter

16

Drugs Used to Treat Poisoning

MANAGEMENT OF POISONING 1. Poisoning is defined as a pathologic state caused by a toxic agent. 2. Sources of poisoning include medications, plants, drug abuse, and environmental pollutants. 3. These toxicants may enter the body orally, by inhalation, and by absorption through the skin. 4. Poisoning may be accidental or intentional. 5. Poisoning occurs at an estimated rate of 5 million per year, and about 6000 deaths result. 6. Approximately 60% of these fatalities are due to ingestion of drugs, either prescription medicines or over-the-counter preparations. The remaining deaths are caused by other chemicals. 7. The incidence of poisoning is highest in young children; however, the mortality rate in this group is low. 8. Most poisoning-related hospital admissions result from suicide attempts by adults.

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Drugs Used to Treat Poisoning ◆ 157 9. In the United States there are more than 500 local poison control centers and over 50 certified regional centers. All of these centers are accessible by phone and can provide immediate instructions on the management of acute poisoning. In the majority of cases, the information supplied will permit successful treatment at home. By facilitating rapid treatment, poison control centers can decrease morbidity and mortality and can help reduce the cost of emergency care. 10. Management of poisoning is a medical emergency and requires rapid treatment. Management has five basic elements: (1) supportive care, (2) identification of the poison, (3) prevention of further absorption, (4) promotion of poison removal, and (5) use of specific antidotes. 11. Supportive care is based on the patient’s clinical status and includes maintenance of respiration and circulation. 12. Careful evaluation of the individual who has been affected by a toxic substance is essential to determine by which route the poison should be removed or eliminated, if necessary. 13. The route of removal is determined by the toxic agent causing the poisoning. Removal can be attempted in several ways: (1) by directly removing it from the stomach, if the poisoning is discovered early; (2) by increasing the rate of transit of poison through the intestines (this may not be effective, as absorption occurs as it moves through the intestines); or (3) if the toxic agent has already been assimilated into the system by injection or late discovery, it is directly removed from the bloodstream using hemoperfusion or peritoneal dialysis. Contact poisons may be flushed from skin and eyes with copious amounts of plain water.

DRUGS USED TO MINIMIZE ABSORPTION OF POISONS 1. The American Academy of Pediatrics recommends that Ipecac syrup should only be administered on the advice of a Poison Control Center or physician, especially in the case of infants and children. This also applies to adults because there are many situations where emesis is contraindicated including poisoning involving strong acids or alkalies, kerosene, gasoline, unconscious, semicomatose, ingestions of sharp objects (e.g., glass, nails) or severely inebriated, patients experiencing convulsions, or patients who have ingested petroleum distillates. The use of ipecac syrup in patients who have ingested petroleum is controversial. Use may be considered in poisoning involving petroleum distillates when the product contains a more toxic ingredient such as heavy metals pesticides; mixed poisonings where the quantity ingested is certain to be toxic. a. Ipecac syrup is available without a prescription in 1 oz. (30 mL) bottles bearing the following instructions. For emergency use to cause vomiting in poisoning. Before using, call physician, poison control center, or hospital emergency room immediately for advice.

158 ◆ Chapter 16 b. Gastric lavage, a nasogastric tube, is put into the stomach and several liters of half-strength saline solution may be used to lavage the stomach. The new Lavacuator tube may also be used. This procedure is repeated until lavage return flows clear. 2. Cathartic and enemas may be used to increase the rate of transit of toxin through the intestines. Saline cathartics (e.g., sodium, magnesium sulfate) are the agents of choice. 3. Activated charcoal may be used following emesis or lavage. The activated charcoal may be instilled or swallowed to act as an absorbent. a. Activated charcoal should be given as soon after poison ingestion as possible. b. Activated charcoal is used as an adjunct in the treatment of oral poisoning with heavy metals, mercuric chloride, strychnine, atropine, mushrooms, aspirin, and most drugs. c. Activated charcoal is not effective for poisoning with cyanide, DDT, ethanol, methanol, caustic alkalis, ferrous sulfate, boric acid, organophosphates, and carbonate. 4. Drugs that enhance renal excretion alter the pH of the urine; this accelerates the excretion of organic acids and bases. An agent that lowers urine pH is ammonium chloride. It renders the urine more acid, decreases the passive reabsorption of the base (e.g., amphetamines, phencyclidine), and thereby enhances their excretion. An agent that increases urine pH is sodium bicarbonate. It renders the urine more alkaline, decreases the passive absorption of acids (e.g., aspirin, phenobarbital), and thereby enhances their excretion. Because of the buffer system present in the blood, sodium bicarbonate and ammonium chloride have relatively little effect on the pH of the blood.

NONDRUG METHODS OF POISON REMOVAL 1. There are several nondrug procedures for removal of toxin from the blood: hemodialysis, hemoperfusion, and exchange transfusion. 2. Peritoneal dialysis has two advantages: the procedure is relatively simple to perform, and it is considered more effective than other procedures. As a result, its use in the management of acute poisoning is increasing. 3. Hemoperfusion is a process in which blood is removed from the body, passed over a column of charcoal or absorbing resin, and then reinfused into the body. If the affinity of the resin for a particular poison is sufficiently high, this procedure can strip a toxin from its binding sites on plasma protein. The principal disadvantage of hemoperfusion is loss of platelets.

SPECIFIC ANTIDOTES USED FOR HEAVY METAL POISONING 1. The heavy metals most frequently responsible for poisoning are lead, iron, mercury, arsenic, gold, and copper.

Drugs Used to Treat Poisoning ◆ 159 2. Useful chelating agents have a high affinity for heavy metals and therefore compete successfully with endogenous molecules for metal binding.

OTHER IMPORTANT ANTIDOTES Throughout this text we have considered the toxic effect of various drugs. When appropriate, we have discussed specific antidotes used to treat these toxicities. For example, when discussing the adverse effects of opioids, we also discussed treatment of opioids overdosage with naloxone (Narcan). Similarly, when we discussed heparin toxicity, we discussed the use of protamine sulfate as treatment.

◆ Heavy Metal Antagonists Generic Name

Trade Name

Specific Metal

Deferoxamine Dimercaprol Edetate calcium disodium Penicillamine Succimer

Desferal Bal in Oil

Iron Gold Calcium EDTA Lead Mercury, lead, copper, iron Lead, mercury, arsenic

• Depen Chemet

The major specific antidotes presented in previous chapters are listed below.

◆ Specific Antidotes Toxic/ Substances Overdosed Generic Name

Trade Name

Naloxone Phytonadione (Vitamin K) Protamine sulfate Glucagon

Narcan AquaMEPHYTON No trade name No trade name

Chapter Opioids (e.g., morphine) Coumadin Heparin Insulin

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