Amiloride is a potassium-sparing diuretic used in heart failure and hypertension. Its mechanism of action involves blockade of which specific channel?

• A Na-K-2Cl cotransporter (NKCC2)
• B Na-Cl cotransporter (NCC)
• C Aquaporin-2 channel
• D Epithelial sodium channel (ENaC) ✓

Explanation

Amiloride and triamterene act on the collecting duct by blocking the epithelial sodium channel (ENaC). This reduces sodium reabsorption and potassium secretion, producing a mild natriuretic effect while conserving potassium. Unlike spironolactone, they do not depend on aldosterone levels for their action.

Reference: Katzung Basic & Clinical Pharmacology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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