Which of the following is a mineralocoicoid antagonist –
**Core Concept**
Mineralocorticoid antagonists are a class of medications that inhibit the effects of mineralocorticoids, specifically aldosterone, by blocking the mineralocorticoid receptor. This leads to increased sodium excretion, decreased potassium excretion, and subsequent diuresis.
**Why the Correct Answer is Right**
The correct mineralocorticoid antagonist is Spironolactone. It works by competing with aldosterone for binding sites on the mineralocorticoid receptor in the collecting duct of the kidney, thereby reducing sodium reabsorption and potassium secretion. This results in increased sodium excretion and decreased potassium excretion, leading to diuresis and a reduction in blood pressure.
**Why Each Wrong Option is Incorrect**
**Option A:** Eplerenone is a selective mineralocorticoid receptor antagonist, but it is not the correct answer in this context. While it is similar to spironolactone, it has a more selective mechanism of action.
**Option B:** Furosemide is a loop diuretic, not a mineralocorticoid antagonist. It works by inhibiting the sodium-potassium-chloride cotransporter in the thick ascending limb of the loop of Henle.
**Option C:** Hydrochlorothiazide is a thiazide diuretic, not a mineralocorticoid antagonist. It works by inhibiting the sodium-chloride cotransporter in the distal convoluted tubule.
**Clinical Pearl / High-Yield Fact**
Mineralocorticoid antagonists like spironolactone are often used in the treatment of heart failure and hypertension, particularly in patients with resistant or refractory disease. They can also be used in the treatment of primary aldosteronism, a condition characterized by excess aldosterone production.
**Correct Answer:** C. Spironolactone