Bio 102 Slide 11

Drugs affecting the Autonomic Nervous System

Unit 11: Pharmacolo gy

Chap 14: Sedative – Hypnotic 1

Nervous System



Drugs that affect the nervous system act upon the: 1. Central Nervous System (CNS) 2. Autonomic Nervous System (ANS)

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Autonomic Nervous System

 Regulatory and selfgoverning  Without conscious thought  Maintains internal environment

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Autonomic Nervous System: Divisions

1. Sympathetic System 

Fight or flight



under stress

3. Parasympathetic System 

Rest and digest

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Innervation  Most organs are innervated by BOTH Sympathetic and Parasympathetic  Keeps a balance of function

 For example:  Heart  Eyes 5

Sympathetic Nervous System Drugs 



Adrenergic (Sympathomimetic) Drugs 

Mimic the action of sympathetic nervous system



For example, Epinephrine (Adrenalin)

Anti-Adrenergic (Sympatholytic) Drugs 

Block the action of sympathetic nervous system



Division: 1. Alpha adrenergic blockers 2. Beta blockers

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Parasympathetic Nervous System Drugs



Cholinergic (Cholinomimetic) drugs 



Stimulate the Parasympathetic Nervous System

Anti-Cholinergic (Cholinolytic) drugs 

Inhibit the Parasympathetic Nervous System 7

Adrenergic (Sympathomimetic)

 Mimic the action of the Sympathetic Nervous System

 Therapeutic uses and adverse effects targets:  Heart, lungs, and blood vessels 8

Adrenergic (Sympathomimetic): Receptors Receptor

Location

Stimulation vasoconstrictions, ↑ BP,

Alpha

blood vessels

↓ nasal congestion, contraction of GIT and urinary bladder sphincter

Beta 1

Beta 2

heart

↑ HR (+) contraction

lungs

bronchodilator

peripheral blood vessels

vasodilation

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Adrenergic (Sympathomimetic): Drugs 1. Cathecholamines 

Cannot cross Blood Brain Barrier



Endogenous: Epinephrine, NE, Dopamine



Exogenous (synthetic): Dobutamine (post-heart failure) and Isoproterenol (Bronchodilators)

3. Non-Cathecholamines 

Cross the Blood Brain Barrier



Ephedrine (Metabolife – diet pills), albuterol (anti-asthma), and phenylephrine (decongestant) 10

Adrenergic (Sympathomimetic): Uses Primarily used for emergency drugs 1. Cardiac arrest – stimulates the heart 2. Hypotension – increase BP 3. CHF – increase force and contraction of heart 4. Asthma – bronchodilator 5. URT Congestion – decongestant 6. Allergic reaction – vasoconstriction and decongestant 7. Hypoglycemia – glycogenolysis 8. Local bleeding – vasoconstriction 9. Obstetrics – uterine relaxant 10. Eye disorder – vasoconstriction

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Adrenergic (Sympathomimetic): Adverse Effects

1. Cathecholamines

1. Non-Cathecholamines



Nervousness and restlessness



Severe anxiety and insonmia



Angina





Hypertension

Tachycardia and palpitations



Dysrhythmias



Muscular weakness and cramps



Tachycardia



Hyperglycemia



Nausea and vomiting 12

Adrenergic (Sympathomimetic): Contraindications

 Cardiac dysrythmia  Angina  Hypertension  Glaucoma  Pregnant women

 Caution with children !! 13

Adrenergic (Sympathomimetic): Cathecholamine Drugs  Epinephrine hydrochloride (Adrenalin Chloride)  Drug of choice for Anaphylaxis  Active ingredient in OTC asthma preparation  Effects: (+) Alpha and Beta recepts  ↑ BP and ↑ HR  ↑ blood flow to brain, heart, and skeletal muscle  Peripheral vasoconstriction  (-) GIT motility

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Adrenergic (Sympathomimetic): Cathecholamine Drugs  Norepinephrine (Levophed)  Strong vasoconstrictor  Used for Hypotension and Cardiac Arrest

 Dopamine Hydrochloride (Intropin)  Precursor to NE  Dosage effects:  Low dose – causes renal perfusion  Low to moderate dose – causes increased CO  Higher doses – increased peripheral resistance and BP 15

Adrenergic (Sympathomimetic): Cathecholamine Drugs  Dobutamine hydrochloride (Dobutrex)  Synthetic cathecholamine  Acts directly on heart muscle to increase the contraction

 Isoproterenol hydrochloride (Isuprel)  Synthetic cathecholamine  Bronchodilator  (+) Beta1 and Beta2 receptors 16

Adrenergic (Sympathomimetic): Anti-Cathecholamine Drugs  Ephedrine and Pseudoephedrine (Sudafed)  Less potent but longer acting than epinephrine  Bronchodilator and Nasal decongestant (allergic reaction)

 Phenylephrine hydrochloride (Neo-Synephrine)  (+) Alpha receptor  Vasoconstrictor, decongestant, and bronchodilator

 Albuterol (Proventil)  Bronchodilator

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Anti-Adrenergic (Sympatholytic)



Block the effect of sympathetic nervous system



Treatment goal is to reduce pathologic response to activity, stress, and other stimuli



Two major types: 1. Alpha-adrenergic blocking agent 2. Beta-adrenergic blocking agent

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Anti-Adrenergic (Alpha-adrenergic): Uses



Mild to moderate hypertension



Benign prostatic hypertrophy (BPH)



Migraine headaches



Pheochromocytoma – tumor of the adrenal glands 

Increased secretion of Epinephrine and NE



CHF with diuretics



Peripheral vascular disorders (frostbites) 19

Anti-Adrenergic (Alpha-adrenergic): Adverse Effects

 Nasal congestion  Nausea  Vomiting  Postural hypotension

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Anti-Adrenergic (Alpha-adrenergic): Contraindications

 Hypersensitivity  Sepsis  Vascular disease  Hepatic or renal disease  Atherosclerosis  Hypertension  Anemia  Pregnancy and lactating  Caution to children and elderly

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Anti-Adrenergic (Alpha-adrenergic): Important Drugs  Phentolamine mesylate (Regitine)  Prevents tissue necrosis after extravasation of IV NE  Prevents and controls hypertension caused by Pheochromocytoma

 Doxazosin (Cardura), Prozosin (Minipress), and Terazosin (Hytrin)  Acts on the periphery  Treats hypertension or BPH

 Sumatriptan (Imitrex)  Vascular headache suppressant to treat migraines 22

Anti-Adrenergic (Beta-Adrenergic)  Block the effect of Adrenergic stimulation of Beta1 or Beta2

 Competes with NE receptor site

 Beta blockers  Decrease in BP, heart contraction, and CO  Beta2 blockers causes vasodilation in skeletal muscles

 Treatment for Angina pectoris and decrease BP

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Anti-Adrenergic (Beta-Adrenergic): Uses

 Angina – decrease in O2 demand, heart contraction, HR, BP  Dysrhythmias – slow sinus node, prolongs AV conduction  Hypertension – lowers BP  MI – to decrease Cathecholamin-induced dysrhythmias  Glaucoma – decreases IOP  Migraine – unclear  Palpitation and Tremor – unapproved anti-anxiety 24

Anti-Adrenergic (Beta-Adrenergic): Adverse Effects  Bradycardia

 Fatigue

 Shortness of breath

 Nausea

 Edema

 Vomiting

 Reduced tolerance to exercise

 Bronchospasm

 Hypoglycemia  CHF

 Impotence  Depression  Sleep disorders

 Orthostatic hypotension 25

Anti-Adrenergic (Beta-Adrenergic): Contraindication

 Diabetes with insulin  Kidney and liver disease (metabolism and excretion)

 Alcohol, CNS depressant, and OTC decongestant

 Not affective for African-Americas 26

Anti-Adrenergic (Beta-Adrenergic): Important Drugs  Propranolol hydrochloride (Inderal)  Treats hypertrophic subaortic stenosis, hypertension, angina, dysrythmias, and MI

 Metoprolol tartrate (Lopressor)  Treats hypertension and dysrythmias

 Atenolol (Tenormin)  Treats hypertension, angina, and MI

 Timolol maleate (Timoptic)  Eye drop for treatment of Glaucoma

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Parasympathetic Nervous System  75% of all parasympathetic fiber are in the Vagus Nerve

 Functions in Rest and Repair

 Found in Digestion, Excretion, Cardiac deceleration, and Anabolism 28

Parasympathetic Nervous System  Acetylcholine is the neurotransmitter

 Stimulation  Constricted pupils  Contraction of GIT smooth muscle  Bronchoconstrictor  Bradycardia  Increased glandular secretion (except sweat) 29

Cholinergic (Parasympathomimetic): Receptors 1. Nicotinic (resembles nicotine) 

Tachycardia



Hypertension



Peripheral vasosconstriction

3. Muscarinic 

Bradycardia



Hypotension



Increase salivation

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Cholinergic (Direct-acting): Effects

 Decreased heart rate  Increased GIT muscle and secretion  Relaxation of sphincters  Increased respiratory secretions  Constriction of pupils 31

Cholinergic (Direct-acting): Uses

 Glaucoma  Gastric reflux  Prevention of nausea & vomiting  Related to chemotherapy

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Cholinergic (Direct-acting): Adverse Effects

 Nausea and Vomiting

 Increased sweating

 Diarrhea

 Impaired vision

 Wheezing & shortness or breath

 Poor night vision

 Bradycardia  Hypotension  Headache  Increased salivation

 Anxiety and restlessness  Sleep disturbance  Convulsion  coma 33

Cholinergic (Direct-acting): Contraindication

 Diabetes mellitus  Coronary artery disease (bradycardia)  MI  Heart block  Intestinal obstruction  Peptic ulcer  Asthma (increased secretion) 34

Cholinergic (Direct-acting): Drugs  Bethanechol chloride (Urecholine)  Treats urinary retention and glaucoma  Pilocarpine hydrochloride (Pilocar)  Decreases IOP in Glaucoma  Carbachol intraocular (Miostat)  Treats Glaucoma  Metoclopramide hydrochloride (Reglan)  Prevents chemotherapy-induced nausea and vomiting  Treats Acid-reflux disease

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Cholinergic (Indirect-acting):

 Inhibit the action of Acetylcholinesterase  Enzyme that breaks down acetylcholine.  Prolongs the effects of Ach

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Cholinergic (Indirect-acting): Uses

 Myasthemia gravis – autoimmune  Decreased neuromuscular transmission  muscle weakness

 Glaucoma  Bladder emptying 37

Cholinergic (Indirect-acting): Adverse Effects

 Hypotension  Miosis – constriction of the pupils  Vasodilation  Bradycardia  Intestinal spasm  Increased salivation  diaphoresis 38

Cholinergic (Indirect-acting): Contraindications

 Diabetes mellitus  Coronary artery disease  Heart block  Urinary tract obstruction  asthma 39

Cholinergic (Indirect-acting): Important drugs  Neostigmine bromide (Prostigmin)  Treats urinary retention

 Edrophonium chloride (Tensilon)  Diagnoses Myasthenia gravis

 Pyridostigmine bromide (mestinon)  Drug of choice for Myasthenia gravis 40

Anti-cholinergic (Parasympatholytic):  Sometimes called Muscarinic antagonist (blocker)  Competes with Ach at the receptor site X

 Depresses the CNS

 Targets the skin, eyes, GIT, urinary bladder, bronchi, and heart

X

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Anti-cholinergic (Parasympatholytic): Uses  Widespread effects on the body. Thus, limits the use

 Treats GIT disorders by increasing motility, secretion, with accompanying pain.

 Urinary disorder – antispasm  Respiratory disorder – causes bronchodilation  Cardiac disease – treats bradycardia  Parkinson’s – decreases salivation and tremors

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Anti-cholinergic (Parasympatholytic): Adverse Effects

 Dry mouth  Constipation  Difficulty urination  Tachycardia  Intolerance to heat 43

Anti-cholinergic (Parasympatholytic): Contraindication

 Glaucoma – drugs causes dilatation of pupil  Hypersensitivity to drug

 Chronic lung, renal, and liver disease  Myasthenia gravis  Heart disease 44

Anti-cholinergic (Parasympatholytic): Drugs  Atropine sulfate  Used to pre-operatively to dry secretions  Treats bradycardia

 Belladonna tincture  Treats GIT disorders

 Hemoatropine (spectro-homatropine)  Eye drops to produce Mydriasis (pupil dilation) and cycloplegia (paralysis of ciliary muscle)

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