A 35-year-old man with confirmed metronidazole-sensitive Trichomonas vaginalis infection is started on metronidazole. He consumes alcohol the same evening and develops severe nausea, vomiting, flushing, and hypotension. This reaction is mechanistically most similar to the effect of which other drug?

• A Fomepizole
• B Naltrexone
• C Acamprosate
• D Disulfiram ✓

Explanation

Metronidazole inhibits aldehyde dehydrogenase (ALDH), the same enzyme inhibited by disulfiram. This causes accumulation of acetaldehyde when alcohol is consumed, producing a disulfiram-like reaction with flushing, nausea, vomiting, and hypotension. Patients must be counselled to avoid alcohol during and for at least 48 hours after metronidazole therapy. Naltrexone is an opioid antagonist, acamprosate modulates glutamate, and fomepizole inhibits alcohol dehydrogenase.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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