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Warfarin antibiotic interaction — GPhC CRA MCQ

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ModerateCardiovascular TherapeuticsWarfarin antibiotic interactionGPhC CRA

A 74-year-old man taking warfarin for AF is prescribed metronidazole for dental infection. His last INR was 2.6. What is the most important interaction to flag?

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

Metronidazole can potentiate warfarin and increase INR, raising the risk of bleeding. The prescriber or anticoagulation clinic should be contacted for management and INR monitoring. The other options do not reflect the clinically important interaction.

Reference: BNF