How do spironolactone and hydrochlorothiazide differ in their effects on potassium?

The correct answer reflects the fact that hydrochlorothiazide is a thiazide diuretic that typically leads to increased potassium excretion. This class of diuretics affects the distal convoluted tubule of the nephron, inhibiting sodium reabsorption, which consequently increases water excretion but also results in a loss of potassium.

On the other hand, spironolactone is a potassium-sparing diuretic. Its mechanism involves antagonism of aldosterone, a hormone that promotes sodium reabsorption and potassium excretion. By blocking the actions of aldosterone, spironolactone not only promotes the excretion of sodium and water but also allows for the retention of potassium.

Therefore, the differential impact on potassium levels is significant. Hydrochlorothiazide, through its diuretic effects, will lead to potassium depletion, while spironolactone will conserve potassium in the body. Understanding these mechanisms is essential in clinical practice, as the choice between these two diuretics may depend on a patient's potassium levels and overall electrolyte balance.