Drug interactions
Atazanavir + Ondansetron
Severity: Moderate
Atazanavir and Ondansetron: 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
Atazanavir inhibits CYP3A4, one of several enzymes that clear ondansetron, so ondansetron exposure may increase modestly. Both drugs can prolong QT or PR intervals, so the effects may add together.
What this interaction means in plain words
Atazanavir and Ondansetron 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.
Atazanavir belongs to Anti Virals; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
CYP3A4 inhibition by atazanavir reduces ondansetron clearance, together with additive cardiac conduction effects.
What to do
No ondansetron dose change is normally required because several pathways clear it. Use the lowest effective dose and consider an ECG in patients with cardiac 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 Atazanavir
- Alfuzosin + Atazanavir Contraindicated
- Atazanavir + Avanafil Contraindicated
- Atazanavir + Dronedarone Contraindicated
- Atazanavir + Eletriptan Contraindicated
- Atazanavir + Eplerenone Contraindicated
- Atazanavir + Ergotamine Contraindicated
Frequently asked questions
Can I take Atazanavir with Ondansetron?
MediHelp rates the interaction as moderate. Atazanavir and Ondansetron 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. Atazanavir inhibits CYP3A4, one of several enzymes that clear ondansetron, so ondansetron exposure may increase modestly. Both drugs can prolong QT or PR intervals, so the effects may add together.
How serious is the interaction between Atazanavir and Ondansetron?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No ondansetron dose change is normally required because several pathways clear it. Use the lowest effective dose and consider an ECG in patients with cardiac 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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