Blocks the hormone aldactone in your body that can raise your blood pressure by constricting your blood vessels and causing you to retain salt and fluid, making your heart failure worsen. Studies have shown that aldactone prolongs life in patients with congestive heart failure. Aldosterone inhibitors are weak diuretics, which hold on to the potassium.

Names of medicines in this group:

Eplerenone (Inspra)
Spironolactone (Aldactone)

Side effects include high potassium, fatigue, enlargement or breast tenderness of one or both breasts in men may be seen with spironolactone only.