What is the mechanism of action for potassium-sparing diuretics?

Potassium-sparing diuretics primarily function by blocking aldosterone receptors, which prevents the action of aldosterone, a hormone that promotes sodium retention and potassium excretion by the kidneys. By inhibiting this action, potassium-sparing diuretics lead to increased sodium and water excretion while conserving potassium in the body. This mechanism is crucial in situations where maintaining potassium levels is desirable, as many other diuretics, such as loop and thiazide diuretics, can cause potassium depletion.

In contrast, options that mention inhibiting sodium reabsorption or acting on the loop of Henle reflect mechanisms associated with other types of diuretics. For example, loop diuretics inhibit sodium reabsorption in the loop of Henle, while thiazide diuretics act on the distal convoluted tubule to inhibit sodium reabsorption. Inhibiting carbonic anhydrase is the mechanism of action for carbonic anhydrase inhibitors, another class of diuretics, which works differently than potassium-sparing diuretics. Therefore, the mechanism of potassium-sparing diuretics is uniquely related to their action on aldosterone receptors, setting them apart from other diuretic classes.