Drug interactions
Moxifloxacin + Ondansetron
Severity: Major
Moxifloxacin 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
Both drugs prolong the QTc interval, and moxifloxacin is among the fluoroquinolones with a greater QT effect. Combined use may increase the risk of torsades de pointes, especially with electrolyte abnormalities or cardiac disease.
What this interaction means in plain words
Moxifloxacin 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.
Moxifloxacin belongs to Anti Bacterial; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
Additive hERG channel blockade producing delayed repolarization.
What to do
Avoid if practicable by using a different antibiotic or antiemetic. If combined, obtain a baseline 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?
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References
- Ondansetron 4 mg film-coated tablets - SmPC sections 4.3/4.5 (class statement: drugs that prolong the QT interval; "Caution should be exercised when ondansetron is coadministered with drugs that prolong the QT interval and/or cause electrolyte abnormalities.") — 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 Moxifloxacin
- Amiodarone + Moxifloxacin Contraindicated
- Arsenic trioxide + Moxifloxacin Contraindicated
- Disopyramide + Moxifloxacin Contraindicated
- Dofetilide + Moxifloxacin Contraindicated
- Dronedarone + Moxifloxacin Contraindicated
- Droperidol + Moxifloxacin Contraindicated
Frequently asked questions
Can I take Moxifloxacin with Ondansetron?
MediHelp rates the interaction as major. Moxifloxacin 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. Both drugs prolong the QTc interval, and moxifloxacin is among the fluoroquinolones with a greater QT effect. Combined use may increase the risk of torsades de pointes, especially with electrolyte abnormalities or cardiac disease.
How serious is the interaction between Moxifloxacin 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 if practicable by using a different antibiotic or antiemetic. If combined, obtain a baseline 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.
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