Drug interactions
Cyproheptadine + Fluoxetine
Severity: Moderate
Cyproheptadine and Fluoxetine: 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
Cyproheptadine's 5-HT2A blockade can oppose the effects of SSRIs, and reduced antidepressant efficacy has been reported with fluoxetine. This is clinically relevant mainly with regular or prolonged cyproheptadine use.
What this interaction means in plain words
Cyproheptadine and Fluoxetine 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.
Cyproheptadine belongs to Respiratory; Fluoxetine belongs to Central Nervous System.
Why it happens
Pharmacodynamic antagonism of serotonin receptors by cyproheptadine counteracts the serotonergic action of fluoxetine.
What to do
Monitor for relapse or worsening depressive or obsessive symptoms during co-therapy. Limit cyproheptadine duration or choose another antihistamine where possible.
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?
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Other interactions of Cyproheptadine
- Cyproheptadine + Isocarboxazid Contraindicated
- Cyproheptadine + Phenelzine Contraindicated
- Cyproheptadine + Tranylcypromine Contraindicated
- Alfentanil + Cyproheptadine Major
- Belladonna and opium + Cyproheptadine Major
- Benzhydrocodone / acetaminophen + Cyproheptadine Major
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 Cyproheptadine with Fluoxetine?
MediHelp rates the interaction as moderate. Cyproheptadine and Fluoxetine 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. Cyproheptadine's 5-HT2A blockade can oppose the effects of SSRIs, and reduced antidepressant efficacy has been reported with fluoxetine. This is clinically relevant mainly with regular or prolonged cyproheptadine use.
How serious is the interaction between Cyproheptadine and Fluoxetine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for relapse or worsening depressive or obsessive symptoms during co-therapy. Limit cyproheptadine duration or choose another antihistamine where possible.
What other medicines interact with Cyproheptadine?
MediHelp also lists interactions of Cyproheptadine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Cyproheptadine page.
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