Aldosterone receptor antagonists (also called an antimineralocorticoid, MCRA, and sometimes MRA) are a class of drugs which block the effects of aldosterone. Aldosterone is the main mineralocorticoid hormone in the body and is produced in the adrenal cortex of the adrenal gland. Aldosterone increases sodium reabsorption by the kidneys, salivary glands, sweat glands and colon. At the same time, it increases the excretion of hydrogen and potassium ions.
By blocking the effects of aldosterone, aldosterone receptor antagonists block the reabsorption of sodium, which encourages water loss. Consequently, this leads to a decrease in blood pressure and a reduction in fluid around the heart.
Aldosterone receptor antagonists may be used in the treatment of high blood pressure or heart failure. They also have a weak diuretic action.