Drug interactions
Fluoxetine + Granisetron
Severity: Moderate
Fluoxetine and Granisetron: 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
Serotonin syndrome has been reported when 5-HT3 antagonists are used with SSRIs such as fluoxetine. Fluoxetine also has a small QT effect that may add to that of granisetron. The overall absolute risk is low.
What this interaction means in plain words
Fluoxetine and Granisetron 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.
Fluoxetine belongs to Central Nervous System; Granisetron belongs to Gastrointestinal Tract.
Why it happens
Possible additive serotonergic effect and modest additive QT prolongation.
What to do
Monitor for serotonin toxicity symptoms and consider an ECG in patients with other QT risk factors. Stop the serotonergic agents and give supportive care if syndrome features appear.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Fluoxetine and Granisetron, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Granisetron
- Apomorphine + Granisetron Contraindicated
- Amiodarone + Granisetron Major
- Amisulpride + Granisetron Major
- Arsenic trioxide + Granisetron Major
- Artemether / lumefantrine + Granisetron Major
- Artemether + Granisetron Major
Other interactions of Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Fluoxetine with Granisetron?
MediHelp rates the interaction as moderate. Fluoxetine and Granisetron 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. Serotonin syndrome has been reported when 5-HT3 antagonists are used with SSRIs such as fluoxetine. Fluoxetine also has a small QT effect that may add to that of granisetron. The overall absolute risk is low.
How serious is the interaction between Fluoxetine and Granisetron?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for serotonin toxicity symptoms and consider an ECG in patients with other QT risk factors. Stop the serotonergic agents and give supportive care if syndrome features appear.
What other medicines interact with Granisetron?
MediHelp also lists interactions of Granisetron with, for example, Apomorphine, Amiodarone, Amisulpride. The full list is on the Granisetron page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
