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Domperidone QT interaction — GPhC CRA MCQ

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HardDrug InteractionsDomperidone QT interactionGPhC CRA

A 55-year-old woman asks to buy domperidone for nausea. She takes erythromycin for a chest infection and has a history of palpitations. Her latest potassium was 3.3 mmol/L. What is the most important interaction to flag?

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Correct answer: D — Domperidone with erythromycin increases cardiac arrhythmia risk

Domperidone is associated with QT prolongation and serious ventricular arrhythmia risk. Erythromycin can also prolong QT and inhibit metabolism, increasing exposure. Hypokalaemia and palpitations add further risk. OTC sale would be inappropriate without medical review.

Reference: https://www.pharmacyregulation.org/students-and-trainees/pharmacist-education-and-training/registration-assessment