What type of diuretic is spironolactone?

Spironolactone is classified as a potassium-sparing diuretic, which helps prevent the loss of potassium that commonly occurs with other types of diuretics. It works by antagonizing aldosterone, a hormone that promotes sodium and water retention while promoting potassium excretion. By blocking aldosterone receptors in the distal convoluted tubule and collecting ducts of the nephron, spironolactone causes the excretion of sodium and water while retaining potassium, making it beneficial for patients who need diuresis without the risk of hypokalemia.

Other diuretic types, such as loop and thiazide diuretics, typically lead to increased potassium excretion, which can lead to potassium depletion. Carbonic anhydrase inhibitors serve a different role, primarily affecting bicarbonate reabsorption in the proximal tubule rather than functioning in a similar manner as potassium-sparing agents. In summary, spironolactone stands out in its ability to conserve potassium while promoting diuresis, which is the defining characteristic of potassium-sparing diuretics.