Drug interactions
Fluoxetine + Tetrabenazine
Severity: Major
Fluoxetine and Tetrabenazine: major interaction.
Last updated Sources: US FDA label
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 QTc interval, so combined use may raise the risk of torsades de pointes. Fluoxetine also strongly inhibits CYP2D6, which raises exposure to the active metabolites of tetrabenazine and increases its adverse effects such as sedation, parkinsonism and depression.
What this interaction means in plain words
Fluoxetine and Tetrabenazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fluoxetine belongs to Central Nervous System; Tetrabenazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation plus CYP2D6 inhibition by fluoxetine that reduces clearance of tetrabenazine's active metabolites.
What to do
Limit the tetrabenazine dose when it is given with a strong CYP2D6 inhibitor, in line with labeling, and obtain a baseline and follow-up ECG. Correct potassium and magnesium, and consider an alternative antidepressant if QTc lengthens.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Fluoxetine and Tetrabenazine, 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.
References
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 Tetrabenazine
- Dronedarone + Tetrabenazine Contraindicated
- Isocarboxazid + Tetrabenazine Contraindicated
- Linezolid + Tetrabenazine Contraindicated
- Phenelzine + Tetrabenazine Contraindicated
- Pimozide + Tetrabenazine Contraindicated
- Procarbazine + Tetrabenazine Contraindicated
Frequently asked questions
Can I take Fluoxetine with Tetrabenazine?
MediHelp rates the interaction as major. Fluoxetine and Tetrabenazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs can prolong the QTc interval, so combined use may raise the risk of torsades de pointes. Fluoxetine also strongly inhibits CYP2D6, which raises exposure to the active metabolites of tetrabenazine and increases its adverse effects such as sedation, parkinsonism and depression.
How serious is the interaction between Fluoxetine and Tetrabenazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit the tetrabenazine dose when it is given with a strong CYP2D6 inhibitor, in line with labeling, and obtain a baseline and follow-up ECG. Correct potassium and magnesium, and consider an alternative antidepressant if QTc lengthens.
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.
