Drug interactions
Fluoxetine + Ritonavir
Severity: Moderate
Fluoxetine and Ritonavir: 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
Ritonavir inhibits CYP2D6 and CYP3A4 and can raise fluoxetine concentrations. Fluoxetine may also raise ritonavir levels, and ritonavir carries QT and serotonergic concerns, so adverse effects of both drugs may increase.
What this interaction means in plain words
Fluoxetine and Ritonavir 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; Ritonavir belongs to Anti Virals.
Why it happens
Ritonavir inhibits CYP2D6 and CYP3A4 metabolism of fluoxetine, with possible reciprocal effects.
What to do
Start fluoxetine at a low dose and titrate slowly. Monitor for serotonergic effects, QT prolongation and antiretroviral toxicity.
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 Ritonavir, 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 Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Fluoxetine with Ritonavir?
MediHelp rates the interaction as moderate. Fluoxetine and Ritonavir 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. Ritonavir inhibits CYP2D6 and CYP3A4 and can raise fluoxetine concentrations. Fluoxetine may also raise ritonavir levels, and ritonavir carries QT and serotonergic concerns, so adverse effects of both drugs may increase.
How serious is the interaction between Fluoxetine and Ritonavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start fluoxetine at a low dose and titrate slowly. Monitor for serotonergic effects, QT prolongation and antiretroviral toxicity.
What other medicines interact with Fluoxetine?
MediHelp also lists interactions of Fluoxetine with, for example, Isocarboxazid, Mavacamten, Methylene blue. The full list is on the Fluoxetine 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.
