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Citalopram and QT-prolonging drug — GPhC CRA MCQ

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HardDrug InteractionsCitalopram and QT-prolonging drugGPhC CRA

A patient taking citalopram is prescribed erythromycin. They have a history of prolonged QT interval documented in clinic letters. What is the most important interaction to flag?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: E — Additive QT prolongation risk

Both medicines can prolong the QT interval and the documented history increases concern. The prescriber should be contacted for an alternative. In this scenario, the correct option is additive QT prolongation risk. 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; Stockley's Drug Interactions