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Clopidogrel-PPI interaction — GPhC CRA MCQ

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HardCardiovascular TherapeuticsClopidogrel-PPI interactionGPhC CRA

A 66-year-old man is taking clopidogrel 75 mg daily following a drug-eluting coronary stent insertion 3 months ago. He presents with worsening gastro-oesophageal reflux and asks if he can start taking omeprazole. What is the most appropriate advice?

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Correct answer: D — Omeprazole should be avoided as it reduces the antiplatelet effect of clopidogrel; consider lansoprazole or pantoprazole instead

Omeprazole and esomeprazole inhibit CYP2C19, the enzyme responsible for converting clopidogrel (a prodrug) to its active metabolite. This interaction can reduce the antiplatelet effect and increase cardiovascular risk. The MHRA advises avoiding concurrent use. Lansoprazole or pantoprazole are preferred alternatives as they have less CYP2C19 inhibitory activity. Separating doses does not adequately mitigate the interaction as the enzyme inhibition is not time-dependent.

Reference: MHRA Drug Safety Update; BNF Drug Interactions