A patient started on enalapril develops a persistent dry cough within two weeks. The mediator responsible for this cough also explains which other well-known ACE inhibitor adverse effect?

• A Hyperkalemia
• B Acute tubular necrosis
• C Angioedema ✓
• D Gingival hyperplasia

Explanation

ACE degrades bradykinin and substance P. Inhibition causes kinin accumulation in the respiratory tract, producing dry cough, and in the oropharyngeal tissues, producing angioedema, which can be life-threatening. Both effects are bradykinin mediated, which is why they are far less frequent with angiotensin receptor blockers. Hyperkalemia (option A) arises instead from reduced aldosterone secretion and is unrelated to kinin metabolism. Patients with cough should be switched to an ARB rather than given a kinin-modifying agent.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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