A patient receiving oral metronidazole for amoebic liver abscess asks whether he may drink beer during the course. The correct advice is to abstain from alcohol:

• A Only on the days the tablet is taken
• B Only if the total daily dose exceeds 2 g
• C Alcohol has no interaction with metronidazole
• D During therapy and for at least 3 days after stopping it ✓

Explanation

Metronidazole produces a disulfiram-like reaction with alcohol: inhibition of aldehyde dehydrogenase causes acetaldehyde accumulation, leading to flushing, throbbing headache, nausea, vomiting and hypotension. Metronidazole persists in the body for some time after the last dose, so abstinence is advised during therapy and for about 3 days afterwards. The reaction is not dose-threshold dependent and occurs even with small amounts of alcohol.

Reference: KD Tripathi Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.