Chapter 13: Diuretic Drugs

The text categorizes diuretics based on their site of action and efficacy, starting with Thiazide and related diuretics, which inhibit the sodium-chloride symporter in the distal tubule; these agents are highlighted for their utility in treating high blood pressure and calcium stones (nephrolithiasis) due to their unique ability to decrease calcium excretion. The summary contrasts these with Loop diuretics, or high-ceiling diuretics, such as furosemide, which target the sodium-potassium-chloride symporter in the thick ascending limb to generate powerful diuresis essential for managing severe pulmonary edema and heart failure, though they carry risks of ototoxicity and significant electrolyte depletion. Potassium-sparing diuretics are examined in two distinct classes—epithelial sodium channel blockers like amiloride and aldosterone receptor antagonists like spironolactone—emphasizing their role in counteracting hypokalemia and treating conditions like hyperaldosteronism and polycystic ovary syndrome. Furthermore, the chapter explores Osmotic diuretics like mannitol, which increase plasma osmotic pressure to treat cerebral edema and acute renal failure, and Carbonic Anhydrase inhibitors like acetazolamide, which act in the proximal tubule to induce metabolic acidosis, making them effective for glaucoma and high-altitude sickness. Finally, the text covers the newer class of Antidiuretic Hormone (ADH) antagonists, or aquaretics, which block vasopressin receptors to promote free water excretion in the treatment of hyponatremia.