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Rifampicin warfarin — GPhC CRA MCQ

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HardDrug InteractionsRifampicin warfarinGPhC CRA

A mechanical-valve patient taking warfarin is started on rifampicin for tuberculosis. What is the most important interaction to flag?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Reduced warfarin effect and lower INR

This scenario assesses Rifampicin warfarin in a UK pharmacy practice context. Rifampicin strongly induces metabolism and can lower warfarin effect. The best answer is Reduced warfarin effect and lower INR because it addresses the principal clinical, legal or safety issue before routine supply. The other options are less appropriate because they either miss the key risk, delay necessary review, or would not meet expected BNF, NICE, MEP, MHRA or GPhC practice standards.

Reference: BNF