Chapter 51 Diuretic Agents Created by Unregisterd version of Xtreme Compressor Chapter 51 Diuretic Agents

Classes of Diuretics Thiazide and thiazide-like diuretics Loop diuretics Carbonic anhydrase inhibitors Potassium-sparing diuretics Osmotic diuretics Created by Unregisterd version of Xtreme Compressor

Function of Diuretic Agents Increase the amount of urine produced by the kidneys Increase sodium excretion Created by Unregisterd version of Xtreme Compressor

Indications for Diuretic Use Edema associated with congestive heart failure Acute pulmonary edema Liver disease (including cirrhosis) Renal disease Hypertension Conditions that cause hyperkalemia Created by Unregisterd version of Xtreme Compressor

Causes of Edema and Ascites in Patients With Liver Failure Reduced plasma protein production Results in less oncotic pull in the vascular system and fluid loss at the capillary level Obstructed blood flow through the portal system Caused by increased pressure from congested hepatic vessels Created by Unregisterd version of Xtreme Compressor

Thiazide and Thiazide-Like Diuretics Hydrochlorothiazide (HydroDIURIL) Chlorothiazide (Diuril) Bendroflumethiazide (Naturetin) Benzthiazide (Exna) Hydroflumethiazide (Diucardin) Methyclothiazide (Aquatensen) Polythiazide (Renese) Trichlormethiazide (Diurese) Created by Unregisterd version of Xtreme Compressor

Sites of Action of Diuretics in the Nephron Created by Unregisterd version of Xtreme Compressor

Indications for Thiazide and Thiazide-Like Diuretics Treatment of edema associated with CHF, liver, or renal disease Monotherapy or adjuncts for the treatment of hypertension Created by Unregisterd version of Xtreme Compressor

Focus on the Prototype Thiazide Diuretic: Hydrochlorothiazide Indications: Adjunctive therapy for edema associated with CHG, cirrhosis, corticosteroid and estrogen therapy, and renal dysfunction; treatment of hypertension Actions: Inhibits reabsorption of sodium and chloride in distal renal tubules, increasing the excretion of sodium, chloride, and water by the kidneys Oral route: Onset 2 h; peak 4–6 h; duration 6–12 h T½: 5.6–14 h; metabolized in the liver and excreted in urine Created by Unregisterd version of Xtreme Compressor

Loop Diuretics Currently Available Furosemide (Lasix) Most commonly used; less powerful than new drugs; larger margin of safety for home use Bumetanide (Bumex) and torsemide (Demadex) New drugs; more powerful than Lasix Ethacrynic acid (Edecrin) First loop diuretic introduced, used less frequently in the clinical setting Created by Unregisterd version of Xtreme Compressor

Indications for Loop Diuretics Acute CHF Acute pulmonary edema Edema associated with CHF Edema associated with renal or liver disease Hypertension Created by Unregisterd version of Xtreme Compressor

Focus on the Loop Diuretic Prototype: Furosemide Indications: Treatment of edema associated with CHF, acute pulmonary edema, hypertension Actions: Inhibits reabsorption of sodium and chloride from the proximal and distal renal tubules and the loop of Henle, leading to a sodium-rich diuresis Oral route: Onset 60 min; peak 60–120 min; duration 6–8 h IV, IM route: Onset 5 min; peak 30 min; duration 2 h T½: 120 min; metabolized in the liver and excreted in urine Created by Unregisterd version of Xtreme Compressor

Focus on the Carbonic Anhydrase Inhibitors Prototype: Acetazolamide (Diamox) Indications: Treatment of glaucoma; edema caused by CHF, drug-induced edema; centrencephalic epilepsy; prophylaxis and treatment of acute altitude sickness Actions: Inhibits carbonic anhydrase, which decreases aqueous humor formation in the eye; intraocular pressure and hydrogen secretion by the renal tubules Routes: Oral, SR, IV T½: 5–6 hr; excreted unchanged in urine Created by Unregisterd version of Xtreme Compressor

Potassium-Sparing Diuretics Types Amiloride (Midamor) Spironolactone (Aldactone) Triamterene (Dyrenium) Uses Patients at high risk for hypokalemia associated with diuretic use Created by Unregisterd version of Xtreme Compressor

Osmotic Diuretics Types Glycerin (Osmoglyn), Isosorbide (Ismotic), Mannitol (Osmitrol), and Urea (Ureaphil) Action Pull water into the renal tubule without sodium loss Indications Increased cranial pressure or acute renal failure due to shock, drug overdose, or trauma Created by Unregisterd version of Xtreme Compressor