Drug interactions
Erythromycin lactobionate + Ondansetron
Severity: Major
Erythromycin lactobionate and Ondansetron: 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
Intravenous erythromycin prolongs the QT interval and ondansetron adds to this effect, increasing the risk of torsades de pointes. Intravenous dosing gives higher peak levels, which makes the effect more pronounced.
What this interaction means in plain words
Erythromycin lactobionate and Ondansetron 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 lactobionate belongs to Anti Bacterial; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
Additive QT prolongation, with possible CYP3A4 inhibition by erythromycin.
What to do
Use an alternative antibiotic or antiemetic where possible. If both are needed, monitor the ECG and correct potassium and magnesium.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Erythromycin lactobionate and Ondansetron, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
- Ondansetron 4 mg film-coated tablets - SmPC sections 4.3/4.5 (names the partner; "antibiotics (such as erythromycin)") — electronic medicines compendium (UK SmPC)
Other interactions of Ondansetron
- Apomorphine + Ondansetron Contraindicated
- Ondansetron + Thioridazine Contraindicated
- Ondansetron + Vandetanib Contraindicated
- Adagrasib + Ondansetron Major
- Amiodarone + Ondansetron Major
- Amisulpride + Ondansetron Major
Other interactions of Erythromycin lactobionate
- Cisapride + Erythromycin lactobionate Contraindicated
- Dihydroergotamine + Erythromycin lactobionate Contraindicated
- Dronedarone + Erythromycin lactobionate Contraindicated
- Eletriptan + Erythromycin lactobionate Contraindicated
- Ergotamine + Erythromycin lactobionate Contraindicated
- Erythromycin lactobionate + Flibanserin Contraindicated
Frequently asked questions
Can I take Erythromycin lactobionate with Ondansetron?
MediHelp rates the interaction as major. Erythromycin lactobionate and Ondansetron 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. Intravenous erythromycin prolongs the QT interval and ondansetron adds to this effect, increasing the risk of torsades de pointes. Intravenous dosing gives higher peak levels, which makes the effect more pronounced.
How serious is the interaction between Erythromycin lactobionate and Ondansetron?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use an alternative antibiotic or antiemetic where possible. If both are needed, monitor the ECG and correct potassium and magnesium.
What other medicines interact with Ondansetron?
MediHelp also lists interactions of Ondansetron with, for example, Apomorphine, Thioridazine, Vandetanib. The full list is on the Ondansetron page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
