Diuretics

DIURETICS Diuretics  increase the rate of urine formation  removal of sodium & water  “ water pills” 2 main indications: 1. decrease blood pressure 2. decrease edema Types of Diuretics: 1. Carbonic Anhydrase inhibitors • acetazolamide (Diamox)* • methazolamide • dichlorphenamide 2. Osmotic Diuretics • mannitol • urea • •

glycerin isosorbide

3. Loop Diuretics • furosemide (Lasix)* • bumetanide • torsemide • ethacrynic

4. Thiazide Diuretics • hydrochlorothiazide (Hydrodiuril) • chlorothiazide Thiazide –like diuretics • chlorthalidone • metolazone 5. Potassium – sparing diuretics • spironolactone •

amiloride • Triamterene

I. Carbonic Anhydrase Inhibitors) MOA: (proximal tubule )  inhibit carbonic anhydrase  prevent exchange of H ions with Na  inhibit H secretion  promote Na ,K & HCO3 excretion  diuresis Indications/ Uses: 1. glaucoma 2. edema secondary to CHF 3. high- altitude sickness SE / Adverse effects: • metabolic acidosis • hypokalemia • paresthesias • drowsiness & confusion

II. Osmotic diuretics MOA: (glomerulus &proximal tubule)  pull water into blood vessels & nephrons from tissues  diuresis Indications: 1. acute renal failure (oliguric phase) 2. increased intracranial pressure 3. cerebral edema SE/ Adverse effects: • headache, confusion • nausea & vomiting • hypotension & lightheadedness • convulsions, shock CI:  anuria , dehydration  heart failure  pulmonary edema

III. Loop Diuretics MOA: (Loop of Henle)  inhibit Na & chloride reabsorption  more Na & water loss  increase renal blood flow by 40%  excrete Na, Cl, K, Mg, Ca Indications: 1. edema assoc. with CHF, liver or kidney dses 2. hypertension SE/Adverse Effects: • dizziness, headache, tinnitus, blurred vision • N & V, diarrhea • agranulocytosis, neutropenia, thrombocytosis • hyponatremia ,hypokalemia,hypocalcemia, hypomagnesemia • hyperglycemia, hyperuricemia

IV. Thiazides & Thiazide-like diuretics MOA: (distal convoluted tubule)  inhibit Na & chloride reabsorption  minor loss of water Indications: 1. edema 2. hypertension SE/Adverse effects: • same CNS & GIT effects of Loop diuretics • Impotence • Urticaria, photosensitivity • hypokalemia, hypomagnesemia • hyperglycemia, hyperlipidemia, hyperuricemia, hypercalcemia

V. Potassium- sparing diuretics MOA: (collecting ducts & distal convoluted tubules)  Inhibit Na – K exchange  Inhibit aldosterone action  Inhibit Na channels Indications: Spironolactone & triamterene 1. hyperaldosteronism 2. hypertension 3. prevent K loss caused by potassium-losing drugs Amiloride 1. CHF SE/Adverse effects: • same CNS & GIT effects as loop diuretics • hyperkalemia • gynecomastia, hirsutism, irregular mense, amenorrhea

Nsg. Implications in giving diuretics:          

Thorough Hx & PE Baseline I & O, serum electrolytes, weight, VS Take in AM Monitor serum K during therapy. Except for K -sparing diuretics, encourage K rich foods. Monitor for digoxin toxicity. Monitor blood glucose when using thiazides/ loop diuretics in diabetic pxs. Change position slowly. Notify physician ASAP for tachycardia , syncope. Monitor for adverse effects:  metabolic alkalosis  drowsiness, lethargy, decreased mental status  hypokalemia  hypotension  tachycardia

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