Drug interactions
Erythromycin ethylsuccinate + Mefloquine
Severity: Major
Erythromycin ethylsuccinate and Mefloquine: major interaction.
Last updated Sources: UK SmPC
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 may increase mefloquine concentrations. Both drugs can prolong the QT interval, so the combination raises the risk of arrhythmia.
What this interaction means in plain words
Erythromycin ethylsuccinate and Mefloquine 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 reduces mefloquine metabolism, with additive QT prolongation.
What to do
Avoid the combination where possible and choose a non-QT-prolonging antibiotic. If unavoidable, monitor the ECG and electrolytes.
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 Mefloquine
- Arsenic trioxide + Mefloquine Contraindicated
- Dronedarone + Mefloquine Contraindicated
- Ibutilide + Mefloquine Contraindicated
- Levoketoconazole + Mefloquine Contraindicated
- Mefloquine + Nilotinib Contraindicated
- Mefloquine + Pimozide Contraindicated
Frequently asked questions
Can I take Erythromycin ethylsuccinate with Mefloquine?
MediHelp rates the interaction as major. Erythromycin ethylsuccinate and Mefloquine 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 may increase mefloquine concentrations. Both drugs can prolong the QT interval, so the combination raises the risk of arrhythmia.
How serious is the interaction between Erythromycin ethylsuccinate and Mefloquine?
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 choose a non-QT-prolonging antibiotic. If unavoidable, monitor the ECG and electrolytes.
What other medicines interact with Mefloquine?
MediHelp also lists interactions of Mefloquine with, for example, Arsenic trioxide, Dronedarone, Ibutilide. The full list is on the Mefloquine page.
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