Drug interactions
Ondansetron + Risperidone
Severity: Moderate
Ondansetron and Risperidone: moderate 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 torsades de pointes. The risk is higher with bradycardia, cardiac disease or low potassium or magnesium.
What this interaction means in plain words
Ondansetron and Risperidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Ondansetron belongs to Gastrointestinal Tract; Risperidone belongs to Central Nervous System.
Why it happens
Additive hERG channel blockade and delayed ventricular repolarization.
What to do
Correct electrolyte disturbances and use the lowest effective ondansetron dose. Obtain an ECG in patients with additional risk factors.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Risperidone
- Ibutilide + Risperidone Contraindicated
- Risperidone + Vandetanib Contraindicated
- Adagrasib + Risperidone Major
- Amiodarone + Risperidone Major
- Amisulpride + Risperidone Major
- Amoxapine + Risperidone Major
Frequently asked questions
Can I take Ondansetron with Risperidone?
MediHelp rates the interaction as moderate. Ondansetron and Risperidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both drugs can prolong the QT interval, so combined use may raise the risk of torsades de pointes. The risk is higher with bradycardia, cardiac disease or low potassium or magnesium.
How serious is the interaction between Ondansetron and Risperidone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Correct electrolyte disturbances and use the lowest effective ondansetron dose. Obtain an ECG in patients with additional risk factors.
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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