Drug interactions
Dosulepin + Fluoxetine
Severity: Major
Dosulepin and Fluoxetine: 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 raises tricyclic antidepressant levels, and dosulepin also has serotonergic activity. This increases the risk of serotonin syndrome, anticholinergic effects, sedation, seizures and cardiac toxicity.
What this interaction means in plain words
Dosulepin and Fluoxetine 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.
Dosulepin belongs to Central Nervous System; Fluoxetine belongs to Central Nervous System.
Why it happens
Additive serotonergic effects with CYP2D6 inhibition by fluoxetine increasing tricyclic exposure.
What to do
Avoid the combination where possible. If used, start dosulepin at a low dose, consider plasma level and ECG monitoring, and watch for serotonin toxicity.
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 Dosulepin
- Dosulepin + Isocarboxazid Contraindicated
- Dosulepin + Phenelzine Contraindicated
- Dosulepin + Thioridazine Contraindicated
- Dosulepin + Tranylcypromine Contraindicated
- Amitriptyline + Dosulepin Major
- Buprenorphine + Dosulepin Major
Frequently asked questions
Can I take Dosulepin with Fluoxetine?
MediHelp rates the interaction as major. Dosulepin and Fluoxetine 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 raises tricyclic antidepressant levels, and dosulepin also has serotonergic activity. This increases the risk of serotonin syndrome, anticholinergic effects, sedation, seizures and cardiac toxicity.
How serious is the interaction between Dosulepin and Fluoxetine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible. If used, start dosulepin at a low dose, consider plasma level and ECG monitoring, and watch for serotonin 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.
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