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Methadone and citalopram — GPhC CRA MCQ

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HardDrug InteractionsMethadone and citalopramGPhC CRA

A 33-year-old man on methadone oral solution 80mg daily is prescribed citalopram 20mg daily. His ECG last year showed borderline prolonged QTc and he occasionally uses cocaine. He asks to collect both from the same pharmacy. What is the most important interaction to flag?

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Correct answer: A — Additive QT interval prolongation risk

Methadone and citalopram can both prolong the QT interval, and a previous borderline QTc increases the clinical importance. Cocaine use can add cardiac risk. The pharmacist should flag the interaction and ensure prescriber review or appropriate monitoring.

Reference: BNF; NICE CKS