A patient started on enalapril develops a persistent dry cough within two weeks. The accumulation of which substance explains this adverse effect?

• A Bradykinin ✓
• B Angiotensin II
• C Substance P
• D Aldosterone

Explanation

ACE degrades bradykinin (a kininase II function), so ACE inhibitors raise bradykinin levels in the respiratory tract, causing dry cough in up to 20 percent of patients. Angiotensin II falls with these drugs and does not cause cough. Substance P rises with ACE inhibitors but the dominant accepted mediator examined in Indian textbooks and Katzung is bradykinin. Switching to an ARB usually resolves it because ARBs do not affect kinin metabolism.

Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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