Drug interactions
Erythromycin ethylsuccinate + Voriconazole
Severity: Major
Erythromycin ethylsuccinate and Voriconazole: 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
Both agents can prolong the QT interval, and voriconazole may increase erythromycin exposure. The combination raises the risk of torsades de pointes.
What this interaction means in plain words
Erythromycin ethylsuccinate and Voriconazole 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
Additive QT prolongation with CYP3A4 inhibition raising erythromycin concentrations.
What to do
Prefer a non-QT-prolonging antibiotic. If combined, obtain baseline ECG, correct potassium and magnesium, and monitor QTc.
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
- VFEND 40 mg/ml powder for oral suspension - SmPC sections 4.3/4.5 (names the partner; "Erythromycin (1 g BID)") — electronic medicines compendium (UK SmPC)
Other interactions of Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
Frequently asked questions
Can I take Erythromycin ethylsuccinate with Voriconazole?
MediHelp rates the interaction as major. Erythromycin ethylsuccinate and Voriconazole 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. Both agents can prolong the QT interval, and voriconazole may increase erythromycin exposure. The combination raises the risk of torsades de pointes.
How serious is the interaction between Erythromycin ethylsuccinate and Voriconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-QT-prolonging antibiotic. If combined, obtain baseline ECG, correct potassium and magnesium, and monitor QTc.
What other medicines interact with Voriconazole?
MediHelp also lists interactions of Voriconazole with, for example, Avanafil, Butabarbital, Carbamazepine. The full list is on the Voriconazole page.
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