Drug interactions
Ondansetron + Toremifene
Severity: Major
Ondansetron and Toremifene: 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
Toremifene causes dose-dependent QT prolongation and is contraindicated in patients with congenital long QT syndrome or on other QT-prolonging drugs. Adding ondansetron increases the risk of serious arrhythmia.
What this interaction means in plain words
Ondansetron and Toremifene 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.
Ondansetron belongs to Gastrointestinal Tract; Toremifene belongs to Endocrine.
Why it happens
Additive pharmacodynamic QT prolongation.
What to do
Avoid the combination and use a non-QT-prolonging antiemetic. If it cannot be avoided, monitor ECG and correct electrolytes.
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 Toremifene
- Amiodarone + Toremifene Contraindicated
- Dronedarone + Toremifene Contraindicated
- Nilotinib + Toremifene Contraindicated
- Pimozide + Toremifene Contraindicated
- Quinidine + Toremifene Contraindicated
- Ribociclib + Toremifene Contraindicated
Frequently asked questions
Can I take Ondansetron with Toremifene?
MediHelp rates the interaction as major. Ondansetron and Toremifene 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. Toremifene causes dose-dependent QT prolongation and is contraindicated in patients with congenital long QT syndrome or on other QT-prolonging drugs. Adding ondansetron increases the risk of serious arrhythmia.
How serious is the interaction between Ondansetron and Toremifene?
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 combination and use a non-QT-prolonging antiemetic. If it cannot be avoided, monitor ECG and correct electrolytes.
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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