Drug interactions
Fluoxetine + Promazine
Severity: Major
Fluoxetine and Promazine: 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 and can raise promazine concentrations, and both drugs can prolong the QT interval. Together they increase the risk of arrhythmia, sedation and anticholinergic effects.
What this interaction means in plain words
Fluoxetine and Promazine 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.
Why it happens
CYP2D6 inhibition by fluoxetine plus additive QT prolongation.
What to do
Obtain an ECG and monitor it during co-therapy, and correct electrolyte abnormalities. Use a lower promazine dose or choose an alternative agent 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?
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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
Frequently asked questions
Can I take Fluoxetine with Promazine?
MediHelp rates the interaction as major. Fluoxetine and Promazine 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 and can raise promazine concentrations, and both drugs can prolong the QT interval. Together they increase the risk of arrhythmia, sedation and anticholinergic effects.
How serious is the interaction between Fluoxetine and Promazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain an ECG and monitor it during co-therapy, and correct electrolyte abnormalities. Use a lower promazine dose or choose an alternative agent 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.
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