Combined pill and enzyme inducer — GPhC CRA MCQ

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ModerateDrug InteractionsCombined pill and enzyme inducerGPhC CRA

A patient using a combined oral contraceptive is started on carbamazepine. What is the most important interaction to flag?

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Correct answer: E — Reduced contraceptive efficacy

Carbamazepine is an enzyme inducer and can reduce hormonal contraceptive efficacy. In this vignette, "Reduced contraceptive efficacy" is the safest single best answer. The other options are less appropriate because they miss the key clinical risk, conflict with UK medicines guidance, or delay needed review.

Reference: https://www.pharmacyregulation.org/registration-assessment#stage-8-order-86