Drug interactions
Erythromycin base + Quinine
Severity: Major
Erythromycin base 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 inhibits CYP3A4 and raises quinine levels, and both drugs prolong the QTc interval. The combination increases the risk of torsades de pointes.
What this interaction means in plain words
Erythromycin base 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.
Why it happens
CYP3A4 inhibition by erythromycin increases quinine exposure, and both drugs add to QT prolongation.
What to do
Avoid the combination where possible and use a non-macrolide antibiotic. If necessary, obtain an ECG, correct electrolytes and monitor for quinine toxicity.
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 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 base with Quinine?
MediHelp rates the interaction as major. Erythromycin base 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 inhibits CYP3A4 and raises quinine levels, and both drugs prolong the QTc interval. The combination increases the risk of torsades de pointes.
How serious is the interaction between Erythromycin base 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 the combination where possible and use a non-macrolide antibiotic. If necessary, obtain an ECG, correct electrolytes and monitor for quinine toxicity.
What other medicines interact with Quinine?
MediHelp also lists interactions of Quinine with, for example, Arsenic trioxide, Dofetilide, Dronedarone. The full list is on the Quinine page.
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