Drug interactions
Fluoxetine + Haloperidol
Severity: Major
Fluoxetine and Haloperidol: 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
Fluoxetine inhibits CYP2D6, which contributes to haloperidol metabolism, so haloperidol levels and the risk of extrapyramidal effects can increase. Both agents can prolong the QT interval, raising the potential for torsades de pointes.
What this interaction means in plain words
Fluoxetine and Haloperidol 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; Haloperidol belongs to Central Nervous System.
Why it happens
Fluoxetine inhibits CYP2D6 metabolism of haloperidol, with additive QT prolongation.
What to do
Use the lowest effective haloperidol dose and monitor for extrapyramidal symptoms and QTc by ECG. Correct electrolyte disturbances and consider an alternative antidepressant if QTc is prolonged.
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?
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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 Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide Contraindicated
Frequently asked questions
Can I take Fluoxetine with Haloperidol?
MediHelp rates the interaction as major. Fluoxetine and Haloperidol 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 inhibits CYP2D6, which contributes to haloperidol metabolism, so haloperidol levels and the risk of extrapyramidal effects can increase. Both agents can prolong the QT interval, raising the potential for torsades de pointes.
How serious is the interaction between Fluoxetine and Haloperidol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective haloperidol dose and monitor for extrapyramidal symptoms and QTc by ECG. Correct electrolyte disturbances and consider an alternative antidepressant if QTc is prolonged.
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.
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