Spironolactone is a potassium sparing diuretic used to treat high blood pressure, congestive heart failure, kidney and liver disease and conditions in which there are abnormally low levels of potassium in the blood.

Spironolactone is a type of medication called a "potassium sparing" diuretic. Diuretics are used to remove a surplus of fluid from the body's bloodstream or tissues. It also acts as an aldosterone inhibitor (prevents salt retention), and is used to treat advanced heart failure when symptoms persist after other drug therapies are maximized. When it is used in this manner, it is not used as a diuretic to remove extra fluid from the body.