skip to main content

Domperidone cardiac risk — GPhC CRA MCQ

Instant feedback + full explanation. One question, done properly.

HardGastrointestinal TherapeuticsDomperidone cardiac riskGPhC CRA

A prescription requests domperidone 10 mg three times daily for a patient taking erythromycin who reports recent palpitations. Which intervention is most appropriate before supply?

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

Reveal the answer and explanation

Correct answer: D — Withhold and contact the prescriber because combined QT prolongation and CYP3A4 inhibition creates a contraindicated cardiac-risk combination

Domperidone is contraindicated with QT-prolonging medicines and potent CYP3A4 inhibitors; erythromycin contributes both pharmacodynamic and pharmacokinetic cardiac risk, especially in a patient with palpitations. Dose spacing, antacid use or a lower domperidone dose does not remove the contraindication. Clarithromycin is also a problematic QT-prolonging CYP3A4 inhibitor, so unilateral substitution would not solve the risk.

Reference: MHRA: domperidone — risks of cardiac side effects. https://www.gov.uk/drug-safety-update/domperidone-risks-of-cardiac-side-effects MHRA: erythromycin — QT prolongation. https://www.gov.uk/drug-safety-update/erythromycin-caution-required-due-to-cardiac-risks-qt-interval-prolongation-drug-interaction-with-rivaroxaban