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Warfarin and metronidazole — GPhC CRA MCQ

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EasyDrug InteractionsWarfarin and metronidazoleGPhC CRA

A patient stabilised on warfarin presents a prescription for metronidazole for dental infection. The latest INR was in range last week. What is the most important interaction to flag?

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Correct answer: B — Metronidazole can increase INR and bleeding risk

Metronidazole can increase the anticoagulant effect of warfarin and raise bleeding risk. The anticoagulation clinic or prescriber should be informed so INR monitoring and dose management can be arranged. The patient should be counselled to report bleeding or bruising promptly.

Reference: BNF