A 55-year-old man started on enalapril develops a persistent dry cough within two weeks. He requires continued blockade of the renin-angiotensin system for diabetic nephropathy. The most appropriate substitution is:
- A Hydrochlorothiazide
- B Amlodipine
- C Losartan ✓
- D Spironolactone
Correct answer: C. Losartan
Explanation
ACE inhibitor cough results from accumulation of bradykinin and substance P, since ACE (kininase II) normally degrades bradykinin. Angiotensin receptor blockers such as losartan block the AT1 receptor without affecting kinin metabolism, so they provide equivalent renin-angiotensin blockade without the cough, and they retain renoprotective benefit in diabetic nephropathy. Amlodipine, hydrochlorothiazide and spironolactone abandon RAS blockade entirely and lose the nephroprotective advantage that prompted therapy in the first place.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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