Spironolactone

Spironolactone (INN, BAN, USAN) (pronounced "SPY-row-no-LACK-tone"), commonly referred to simply as "spiro", and marketed primarily under the brand name Aldactone in most countries, is a synthetic, steroidal antimineralocorticoid agent with additional antiandrogen and weak progestogen properties, as well as some indirect estrogen and glucocorticoid effects, which is used primarily as a diuretic and antihypertensive, but also for the purpose of reducing elevated or unwanted androgen activity in the body. It acts predominantly as a competitive antagonist of the aldosterone (or mineralocorticoid) receptor, and belongs to a class of pharmaceutical drugs known as potassium-sparing diuretics.

Spironolactone is a relatively old drug, having been introduced clinically in 1959. It has been mostly superseded in cardiovascular conditions (e.g., heart failure and hypertension) by the newer agents such as the structurally related compound eplerenone, which is also an aldosterone antagonist but is selective and lacks many of the actions and side effects of spironolactone, and as such is much more tolerable in comparison. However, spironolactone nonetheless still finds frequent use as an antiandrogen.