A diuretic is any substance that promotes diuresis, that is, the increased production of urine. This includes forced diuresis. Diuretic includes loop diuretics, potassium sparing diuretics, thiazide and thiazide-like diuretics, carbonic anhydrase inhibitors, and osmotic diuretics. Loop diuretics include bumetanide, furosemide, and torsemide. Potassium sparing diuretics include amiloride, spironolactone and triamterene. Thiazide and thiazide-like diuretics include chlorthalidone, hydrochlorothiazide, indapamide and metolazone. Action, uses, dosages and side effects of all these drugs are also covered in this chapter. Common side effects are diarrhea, nausea, tinnitus, dehydration, hypokalemia, hypochloremia, hyponatremia, metabolic alkalosis, and hypovolemia. Serious side effects include renal failure, hearing loss, and circulatory collapse.