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Carbamazepine enzyme induction — GPhC CRA MCQ

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HardCNS TherapeuticsCarbamazepine enzyme inductionGPhC CRA

A patient taking carbamazepine asks for emergency contraception after unprotected sex. They are within 48 hours. What is the most important interaction to flag?

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Correct answer: CEnzyme induction can reduce hormonal emergency contraception effectiveness

Carbamazepine is an enzyme inducer and can reduce effectiveness of levonorgestrel and ulipristal. Copper intrauterine contraception or guideline-based alternatives should be discussed urgently. In this scenario, the correct option is enzyme induction can reduce hormonal emergency contraception effectiveness. The other options are plausible but do not address the key clinical, legal or safety issue as directly. This aligns with UK pharmacy practice guidance cited in the reference field.

Reference: BNF; FSRH; MEP