What must a patient taking metronidazole avoid during treatment and for 72 hours after?

Patients taking metronidazole need to avoid alcohol during treatment and for at least 72 hours after completion. This is because metronidazole can cause a disulfiram-like reaction when taken with alcohol, leading to unpleasant symptoms such as flushing, nausea, vomiting, and abdominal cramps. This reaction occurs because metronidazole inhibits the enzyme aldehyde dehydrogenase, which is involved in metabolizing alcohol, resulting in an accumulation of acetaldehyde in the body.

While avoiding caffeinated beverages, carbonated drinks, and high-sugar foods might be advisable for other health reasons or due to personal tolerance, these are not specifically contraindicated or known to interact negatively with metronidazole in the same way alcohol does. Therefore, the need to avoid alcohol is crucial for patient safety during metronidazole therapy.