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Warfarin and amiodarone — GPhC CRA MCQ

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ModerateDrug InteractionsWarfarin and amiodaroneGPhC CRA

A patient stabilised on warfarin is started on amiodarone after a cardiology review. He asks whether his anticoagulant dose can stay the same. What is the most important interaction to flag?

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Correct answer: D — Amiodarone can increase warfarin effect and INR

Amiodarone can inhibit warfarin metabolism and increase anticoagulant effect, raising INR and bleeding risk. The interaction may develop over time because amiodarone has a long half-life. Closer INR monitoring and dose adjustment may be needed. The INR test remains valid and is central to management.

Reference: BNF