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Methadone and citalopram — GPhC CRA MCQ

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HardDrug InteractionsMethadone and citalopramGPhC CRA

A patient taking methadone 80 mg daily is prescribed citalopram 20 mg daily for depression. They have a previous ECG showing borderline QT prolongation. What is the most important interaction to flag?

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Correct answer: D — Increased risk of QT interval prolongation

Both methadone and citalopram can prolong the QT interval, and a history of borderline QT prolongation increases concern. The prescriber should assess ECG risk, alternative antidepressants and monitoring. Depression treatment may still be needed, but the cardiac risk should be actively managed. Symptoms such as syncope or palpitations need urgent review.

Reference: https://www.pharmacyregulation.org/registration-assessment#stage-8-order-36