AEMCA Practice Exam

What action does the potassium-sparing diuretic spironolactone inhibit?

1. Inhibits sodium chloride reabsorption

2. Inhibits aldosterone action

3. Inhibits potassium secretion

4. Inhibits water retention

The correct answer is: Inhibits aldosterone action

Spironolactone is a potassium-sparing diuretic that specifically inhibits the action of aldosterone. Aldosterone is a steroid hormone that plays a crucial role in regulating sodium and potassium balance in the body. It stimulates the kidneys to reabsorb sodium and water while promoting the excretion of potassium. By blocking aldosterone's effects, spironolactone leads to increased excretion of sodium and water, while reducing potassium loss. This mechanism results in a diuretic effect without the potassium-wasting effects commonly seen with other diuretics. As a result, spironolactone is often used not only to manage fluid retention but also to prevent hypokalemia (low potassium levels). The other options deal with related processes but do not specifically capture spironolactone's primary mechanism of action. For example, while inhibiting sodium chloride reabsorption and potassium secretion are outcomes of its action, the core mechanism remains its inhibition of aldosterone. Similarly, water retention and its inhibition may result from other physiological actions but are not the direct effect of spironolactone in this context.