Which of the following drugs is a recognised cause of gynaecomastia?
- A Metoprolol
- B Frusemide
- C Spironolactone ✓
- D Amoxicillin
Correct answer: C. Spironolactone
Explanation
Spironolactone causes gynaecomastia by displacing testosterone from sex hormone binding globulin and blocking androgen receptors, producing a relative oestrogen effect. Other classic offenders include cimetidine, digoxin, oestrogens, ketoconazole and marijuana. Frusemide, metoprolol and amoxicillin are not established causes. In exam questions, spironolactone is the single most frequently tested drug cause, so recognising it separates candidates who know the pharmacological mechanisms from those guessing among diuretics.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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