Drug interactions
Erythromycin + Quinine
Severity: Major
Erythromycin and Quinine: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Erythromycin raises quinine concentrations and both drugs prolong the QT interval. The combination increases the risk of torsades de pointes and cinchonism.
What this interaction means in plain words
Erythromycin and Quinine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Erythromycin belongs to Anti Bacterial; Quinine belongs to Anti Parasitic.
Why it happens
CYP3A4 inhibition by erythromycin increases quinine exposure, with additive hERG-mediated QT prolongation.
What to do
Avoid if possible, choosing a non-QT-prolonging antibiotic. If combined, obtain an ECG, correct electrolytes and monitor for cinchonism.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin Contraindicated
Other interactions of Quinine
- Arsenic trioxide + Quinine Contraindicated
- Dofetilide + Quinine Contraindicated
- Dronedarone + Quinine Contraindicated
- Ibutilide + Quinine Contraindicated
- Mefloquine + Quinine Contraindicated
- Nilotinib + Quinine Contraindicated
Frequently asked questions
Can I take Erythromycin with Quinine?
MediHelp rates the interaction as major. Erythromycin and Quinine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Erythromycin raises quinine concentrations and both drugs prolong the QT interval. The combination increases the risk of torsades de pointes and cinchonism.
How serious is the interaction between Erythromycin and Quinine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible, choosing a non-QT-prolonging antibiotic. If combined, obtain an ECG, correct electrolytes and monitor for cinchonism.
What other medicines interact with Erythromycin?
MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.
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