2024 NCMA216 PHARM Renal Diuretics PDF

RENAL DIURETICS NCMA216 PHAR BSN 1STSEM 2024- 2025 DR SONNIE P TALAVERA DIURETI CS AGENTS Diuretic Agents  Drugs that accelerate the rate of urine formation.  Result: removal of sodium and water Sodium  Where sodium goes, water follows.  20 to 25% of all sodium is rea...

RENAL DIURETICS NCMA216 PHAR BSN 1STSEM 2024- 2025 DR SONNIE P TALAVERA DIURETI CS AGENTS Diuretic Agents  Drugs that accelerate the rate of urine formation.  Result: removal of sodium and water Sodium  Where sodium goes, water follows.  20 to 25% of all sodium is reabsorbed into the bloodstream in the loop of Henle, 5 to 10% in the distal tubules, and 3% in collecting ducts. Diuretic Agents  Carbonic anhydrase inhibitors  Loop diuretics  Osmotic diuretics  Potassium-sparing diuretics  Thiazide and thiazide-like diuretics Carbonic Anhydrase Inhibitors (CAIs)  acetazolamide (Diamox)  methazolamide  dichlorphenamide Carbonic Anhydrase Inhibitors: Mechanism of Action  The enzyme carbonic anhydrase helps to make H+ ions available for exchange with sodium and water in the proximal tubules.  CAIs block the action of carbonic anhydrase, thus preventing the exchange of H+ ions with sodium and water. Carbonic Anhydrase Inhibitors: Mechanism of Action  Inhibition of carbonic anhydrase reduces H+ ion concentration in renal tubules.  As a result, there is increased excretion of bicarbonate, sodium, water, and potassium.  Resorption of water is decreased Carbonic Anhydrase Inhibitors: Therapeutic Uses  Adjunct agents in the long-term management of open-angle glaucoma  Used with miotics to lower intraocular pressure before ocular surgery in certain cases  Also useful in the treatment of:  Glaucoma  Edema  Epilepsy  High-altitude sickness Carbonic Anhydrase Inhibitors: Therapeutic Uses  Acetazolamide is used in the management of edema secondary to CHF when other diuretics are not effective.  CAIs are less potent diuretics than loop diuretics or thiazides—the metabolic acidosis they induce reduces their diuretic effect in 2 to 4 days. Carbonic Anhydrase Inhibitors: Side Effects Metabolic acidosis Drowsiness Anorexia Paresthesias Hematuria Urticaria PhotosensitivityMelena Loop Diuretics  bumetanide (Bumex)  ethacrynic acid (Edecrin)  furosemide (Lasix) Loop Diuretics: Mechanism of Action  Act directly on the ascending limb of the loop of Henle to inhibit sodium and chloride resorption.  Increase renal prostaglandins, resulting in the dilation of blood vessels and reduced peripheral vascular resistance. Loop Diuretics: Drug Effects  Potent diuresis and subsequent loss of fluid  Decreased fluid volume causes:  Reduced BP  Reduced pulmonary vascular resistance  Reduced systemic vascular resistance  Reduced central venous pressure  Reduced left ventricular end-diastolic pressure  Potassium depletion Loop Diuretics: Therapeutic Uses  Edema associated with CHF or hepatic or renal disease  Control of hypertension Loop Diuretics: Side Effects Body System Effect CNS Dizziness, headache, tinnitus, blurred vision GI Nausea, vomiting, diarrhea Loop Diuretics: Side Effects Body System Effect Hematologic Agranulocytosis, neutropenia, thrombocytopenia Metabolic Hypokalemia, hyperglycemia, hyperuricemia Osmotic Diuretics  mannitol (Resectisol, Osmitrol) Osmotic Diuretics: Mechanism of Action  Work in the proximal tubule  Nonabsorbable, producing an osmotic effect  Pull water into the blood vessels and nephrons from the surrounding tissues Osmotic Diuretics: Drug Effects  Reduced cellular edema  Increased urine production, causing diuresis  Rapid excretion of water, sodium, and other electrolytes, as well as excretion of toxic substances from the kidney  Reduces excessive intraocular Osmotic Diuretics: Therapeutic Uses  Used in the treatment of patients in the early, oliguric phase of ARF  To promote the excretion of toxic substances  Reduction of intracranial pressure  Osmotic Diuretics: Side Effects  Convulsions  Thrombophlebitis  Pulmonary congestion Also headaches, chest pains, tachycardia, blurred vision, chills, and fever Potassium-Sparing Diuretics  amiloride (Midamor)  spironolactone (Aldactone)  triamterene (Dyrenium) Potassium-Sparing Diuretics: Mechanism of Action  Work in collecting ducts and distal convoluted tubules  Interfere with sodium-potassium exchange  Competitively bind to aldosterone receptors  Block the resorption of sodium and water usually induced by Potassium-Sparing Diuretics: Drug Effects  Prevent potassium from being pumped into the tubule, thus preventing its secretion  Competitively block the aldosterone receptors and inhibit its action  The excretion of sodium and water is promoted Potassium-Sparing Diuretics: Therapeutic Uses spironolactone and triamterene  Hyperaldosteronism  Hypertension  Reversing the potassium loss caused by  potassium-losing drugs amiloride  Treatment of CHF Potassium-Sparing Diuretics: Side Effects Body System Effect CNS Dizziness, headache GI Cramps, nausea, vomiting, diarrhea Other Urinary frequency, weakness **hyperkalemia Potassium-Sparing Diuretics: Side Effects spironolactone  gynecomastia, amenorrhea, irregular menses Thiazide and Thiazide-Like Diuretics  hydrochlorothiazide (Esidrix, HydroDIURIL)  chlorothiazide (Diuril)  trichlormethiazide (Metahydrin)  Thiazide-like  chlorthalidone (Hygroton)  metolazone (Mykrox, Zaroxolyn) Thiazide and Thiazide-Like Diuretics: Mechanism of Action  Inhibit tubular resorption of sodium and chloride ions  Action primarily in the ascending loop of Henle and early distal tubule  Result: water, sodium, and chloride are excreted  Potassium is also excreted to a lesser extent  Dilate the arterioles by direct relaxation Thiazide and Thiazide-Like Diuretics: Drug Effects  Lowered peripheral vascular resistance  Depletion of sodium and water Thiazide and Thiazide-Like Diuretics: Therapeutic Uses  Hypertension (one of the most prescribed group of agents for this)  Edematous states  Idiopathic hypercalciuria  Diabetes insipidus  Adjunct agents in treatment of CHF, hepatic cirrhosis Thiazide and Thiazide-Like Diuretics: Side Effects Body System Effect CNS Dizziness, headache, blurred vision, paresthesias, decreased libido GI Anorexia, nausea, vomiting, diarrhea Thiazide and Thiazide-Like Diuretics: Side Effects Body System Effect GU Impotence Integumentary Urticaria, photosensitivity Metabolic Hypokalemia, glycosuria, hyperglycemia CLINICAL NOTES Diuretic Agents  Perform a thorough patient history and physical examination.  Assess baseline fluid volume status, intake and output, serum electrolyte values, weight, and vital signs.  Assess for disorders that may contraindicate the use of, or necessitate cautious use of, these agents. Diuretic Agents  Instruct patients to take in the morning as much as possible to avoid interference with sleep patterns.  Monitor serum potassium levels during therapy.  Potassium supplements are usually not recommended when potassium levels exceed 3.0 mEq/L. Diuretic Agents  Teach patients to maintain proper nutritional and fluid volume status.  Teach patients to eat more potassium- rich foods when taking any but the potassium-sparing agents.  Foods high in potassium include bananas, oranges, dates, raisins, plums, fresh vegetables, potatoes, meat, and fish. Diuretic Agents  Patients taking diuretics along with a digitalis preparation should be taught to monitor for digitalis toxicity.  Diabetic patients who are taking thiazide and/or loop diuretics should be told to monitor blood glucose and watch for elevated levels. Diuretic Agents  Teach patients to change positions slowly, and to rise slowly after sitting or lying to prevent dizziness and possible fainting related to orthostatic hypotension.  Encourage patients to keep a log of their daily weight.  Encourage patients to return for follow-up visits and lab work. Diuretic Agents  Patients who have been ill with nausea, vomiting, and/or diarrhea should notify their physician as fluid loss may be dangerous.  Signs and symptoms of hypokalemia include muscle weakness, constipation, irregular pulse rate, and overall feeling of lethargy. Diuretic Agents  Instruct patients to notify the physician immediately if they experience rapid heart rates or syncope (reflects hypotension or fluid loss).  A weight gain of 2 or more pounds a day or 5 or more pounds a week should be reported immediately. Diuretic Agents Monitor for adverse effects:  metabolic alkalosis, drowsiness, lethargy, hypokalemia, tachycardia, hypotension, leg cramps, restlessness, decreased mental alertness Diuretic Agents  Monitor for therapeutic effects:  Reduction in edema, fluid volume overload, CHF  Reduction of hypertension  Return to normal intraocular pressures