Pharmacology · single question
What is the most important instruction to give a patient who has been prescribed metronidazole?
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Correct answer: A. Avoid alcohol during and for 48 hours after completing the course
Metronidazole inhibits the enzyme aldehyde dehydrogenase, causing a disulfiram-like reaction when combined with alcohol. This reaction produces nausea, vomiting, flushing, tachycardia, and hypotension. Patients must avoid all alcohol (including alcohol-containing mouthwashes and medications) during the course and for at least 48 hours after the last dose. This is the most critical drug interaction and patient counseling point for metronidazole.