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Citalopram and QT prolongation — GPhC CRA MCQ

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ModerateCNS TherapeuticsCitalopram and QT prolongationGPhC CRA

A 68-year-old man takes citalopram 40mg daily and is prescribed clarithromycin for chest infection. His records show a history of prolonged QT interval. The prescriber asks for pharmacy advice. What is the most important interaction to flag?

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Correct answer: B — QT interval prolongation risk is increased with this combination

Citalopram can prolong the QT interval, and clarithromycin also carries QT-prolongation risk and can increase exposure to some medicines. A patient with previous QT prolongation is at higher risk. The prescriber should consider an alternative antibiotic and review the antidepressant dose.

Reference: BNF