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Clozapine and smoking cessation — GPhC CRA MCQ

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HardDrug InteractionsClozapine and smoking cessationGPhC CRA

A patient taking clozapine has stopped smoking abruptly during a hospital admission. The ward asks why the clozapine dose may need review. What is the most important interaction to flag?

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Correct answer: E — Stopping smoking can increase clozapine concentrations and toxicity risk

Tobacco smoke induces CYP1A2, which contributes to clozapine metabolism. Stopping smoking can increase clozapine concentrations and toxicity risk, even if nicotine replacement is used. The dose and plasma levels may need specialist review. Symptoms such as sedation, confusion or seizures are concerning.

Reference: BNF; NICE CKS