Diuretics, also called water pills, are medications that act on the kidneys to increase diuresis, or the production of urine, to help excrete more water from the body. Therefore, they are generally used to treat hypertension, as well as edema caused by fluid overload conditions, such as heart failure and pulmonary edema, as well as renal diseases like nephrotic syndrome, and hepatic diseases like cirrhosis. Diuretics are most often administered orally, but some of them can also be administered intravenously.
Once administered, these diuretics act on the kidneys’ basic unit, the nephron, to induce electrolyte and water excretion.
Zooming into the nephron, it’s made up of a glomerulus, which filters the blood. The filtered content goes through the renal tubules, which have four parts: the proximal convoluted tubule; the U-shaped loop of Henle, with a thin descending, a thin ascending, and a thick ascending limb; the distal convoluted tubule; and the collecting duct, which drain the urine out of the kidneys.
Now, the main classes of diuretics include thiazide and thiazide-like diuretics, loop diuretics, and potassium sparing diuretics.
Okay, starting with thiazide diuretics and thiazide-like diuretics, which have a slightly different structure but act in the same way. Available thiazide diuretics include chlorothiazide and hydrochlorothiazide, while examples of thiazide-like diuretics are chlorthalidone and indapamide.