Aldosterone receptor antagonists are medicines that help the body get rid of extra water (diuretics). They also have other properties that can prevent heart failure from becoming worse, along with improving symptoms of heart failure. These medicines cause the kidneys to get rid of extra water and they help hold on to (retain) potassium by inhibiting the action of the hormone aldosterone. Because of this, they are called potassium-sparing diuretics. Examples: eplerenone, spironolactone.