Aldosterone antagonist

Antimineralocorticoid
Drug class
Spironolactone, the most widely used antimineralocorticoid.
Class identifiers
Synonyms	Aldosterone antagonist; Mineralocorticoid antagonist
Use	Diuretic; Chronic heart failure; Hypertension; Hyperaldosteronism; Conn's syndrome
Biological target	Mineralocorticoid receptor
Chemical class	Steroidal; Non-steroidal

An antimineralocorticoid, MCRA, or an aldosterone antagonist, is a diuretic drug which antagonizes the action of aldosterone at mineralocorticoid receptors. This group of drugs is often used as adjunctive therapy, in combination with other drugs, for the management of chronic heart failure. Spironolactone, the first member of the class, is also used in the management of hyperaldosteronism (including Conn's syndrome) and female hirsutism (due to additional antiandrogen actions). Most antimineralocorticoids, including spironolactone, are steroidal spirolactones. Finerenone is a non-steroidal antimineralocorticoid.

Aldosterone antagonists are, as the name suggests, receptor antagonists at the mineralocorticoid receptor. Antagonism of these receptors inhibits sodium resorption in the collecting duct of the nephron in the kidneys. This interferes with sodium/potassium exchange, reducing urinary potassium excretion and weakly increasing water excretion (diuresis).

In congestive heart failure, they are used in addition to other drugs for additive diuretic effect, which reduces edema and the cardiac workload.