Drug interactions
Grapefruit + Ondansetron
Severity: Minor
Grapefruit and Ondansetron: minor 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
Grapefruit juice inhibits intestinal CYP3A4 and may modestly raise ondansetron exposure. Since ondansetron has several clearance pathways, a clinically important change is unlikely.
What this interaction means in plain words
Grapefruit and Ondansetron have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Inhibition of intestinal CYP3A4 by grapefruit furanocoumarins reduces first-pass metabolism.
What to do
No restriction is usually needed. Patients with QT risk factors may be advised to avoid large amounts of grapefruit juice.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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
Frequently asked questions
Can I take Grapefruit with Ondansetron?
MediHelp rates the interaction as minor. Grapefruit and Ondansetron have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Grapefruit juice inhibits intestinal CYP3A4 and may modestly raise ondansetron exposure. Since ondansetron has several clearance pathways, a clinically important change is unlikely.
How serious is the interaction between Grapefruit and Ondansetron?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No restriction is usually needed. Patients with QT risk factors may be advised to avoid large amounts of grapefruit juice.
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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