Drug interactions
Mefloquine + Ondansetron
Severity: Major
Mefloquine 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
Mefloquine can alter cardiac conduction and prolong the QT interval, and ondansetron may add to this effect. The combination may increase the risk of torsades de pointes, particularly in patients with cardiac disease or electrolyte disturbances.
What this interaction means in plain words
Mefloquine 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.
Mefloquine belongs to Anti Parasitic; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
Additive QT prolongation and effects on cardiac conduction.
What to do
Avoid if possible and choose another antimalarial or antiemetic. If combined, obtain 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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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 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 Mefloquine with Ondansetron?
MediHelp rates the interaction as major. Mefloquine 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. Mefloquine can alter cardiac conduction and prolong the QT interval, and ondansetron may add to this effect. The combination may increase the risk of torsades de pointes, particularly in patients with cardiac disease or electrolyte disturbances.
How serious is the interaction between Mefloquine 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 possible and choose another antimalarial or antiemetic. If combined, obtain 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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