Which antihypertensive medication is classified as a potassium-sparing diuretic?

Spironolactone is classified as a potassium-sparing diuretic, which means it helps to reduce fluid retention and lower blood pressure while minimizing the loss of potassium. Unlike other diuretics that can lead to potassium depletion, spironolactone works by antagonizing the action of aldosterone in the kidneys, leading to increased excretion of sodium and water while retaining potassium. This unique mechanism is especially beneficial in patients who are at risk for hypokalemia or who need to manage conditions associated with excess aldosterone, such as primary hyperaldosteronism or heart failure.

The other medications listed have different classifications and effects. Furosemide is a loop diuretic that can cause significant potassium loss. Amlodipine is a calcium channel blocker primarily used to treat hypertension by dilating blood vessels. Hydrochlorothiazide is a thiazide diuretic, which also tends to lead to potassium loss. These distinctions highlight the specific role of spironolactone in managing hypertension while preserving potassium levels in the body.