Drug interactions
Hydroxychloroquine + Ondansetron
Severity: Major
Hydroxychloroquine 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
Both drugs can prolong the QT interval, so combined use may raise the risk of ventricular arrhythmias including torsades de pointes. Risk rises with electrolyte abnormalities, heart disease or additional QT-prolonging agents.
What this interaction means in plain words
Hydroxychloroquine 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.
Hydroxychloroquine belongs to Musculoskeletal; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
Additive delayed ventricular repolarization through potassium channel blockade.
What to do
Check baseline ECG and electrolytes and repeat ECG if risk factors exist. Consider an alternative antiemetic with less QT effect, such as one outside the 5-HT3 class.
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 Hydroxychloroquine
- Arsenic trioxide + Hydroxychloroquine Contraindicated
- Cisapride + Hydroxychloroquine Contraindicated
- Dronedarone + Hydroxychloroquine Contraindicated
- Hydroxychloroquine + Pimozide Contraindicated
- Hydroxychloroquine + Thioridazine Contraindicated
- Hydroxychloroquine + Vandetanib Contraindicated
Frequently asked questions
Can I take Hydroxychloroquine with Ondansetron?
MediHelp rates the interaction as major. Hydroxychloroquine 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 can prolong the QT interval, so combined use may raise the risk of ventricular arrhythmias including torsades de pointes. Risk rises with electrolyte abnormalities, heart disease or additional QT-prolonging agents.
How serious is the interaction between Hydroxychloroquine 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: Check baseline ECG and electrolytes and repeat ECG if risk factors exist. Consider an alternative antiemetic with less QT effect, such as one outside the 5-HT3 class.
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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