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Macrolide and QT prolongation — GPhC CRA MCQ

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HardDrug InteractionsMacrolide and QT prolongationGPhC CRA

A 77-year-old woman taking sotalol is prescribed clarithromycin for a respiratory infection. Her latest ECG showed borderline QT prolongation. She has normal renal function. What monitoring is required?

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Correct answer: C — ECG and electrolyte review if treatment cannot be changed

Both clarithromycin and sotalol can prolong the QT interval. Combining QT-prolonging medicines increases risk of torsades de pointes, especially in older patients or those with existing QT prolongation. The prescriber should consider an alternative antibiotic or an appropriate monitoring plan.

Reference: BNF