Drug interactions
Lefamulin + Ondansetron
Severity: Major
Lefamulin and Ondansetron: major interaction.
Last updated
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
Lefamulin inhibits CYP3A4 and itself prolongs the QT interval. Ondansetron also prolongs QT, so exposure and pharmacodynamic effects add up and raise the risk of torsades de pointes.
What this interaction means in plain words
Lefamulin 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.
Lefamulin belongs to Anti Bacterial; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
CYP3A4 inhibition raises ondansetron levels, with additive QT prolongation.
What to do
Avoid the oral lefamulin formulation with ondansetron where possible. If both are needed, use ECG monitoring 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?
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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 Lefamulin
- Lefamulin + Methadone Contraindicated
- Lefamulin + Pimavanserin Contraindicated
- Lefamulin + Pimozide Contraindicated
- Lefamulin + Quinidine Contraindicated
- Alfuzosin + Lefamulin Major
- Amiodarone + Lefamulin Major
Frequently asked questions
Can I take Lefamulin with Ondansetron?
MediHelp rates the interaction as major. Lefamulin 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. Lefamulin inhibits CYP3A4 and itself prolongs the QT interval. Ondansetron also prolongs QT, so exposure and pharmacodynamic effects add up and raise the risk of torsades de pointes.
How serious is the interaction between Lefamulin 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: Avoid the oral lefamulin formulation with ondansetron where possible. If both are needed, use ECG monitoring 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.
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