Drug interactions
Butorphanol + Fenfluramine
Severity: Moderate
Butorphanol and Fenfluramine: 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
Fenfluramine is an antiseizure drug that commonly causes somnolence and fatigue, so it may add to butorphanol sedation instead of opposing it. The effect has not been well characterised.
What this interaction means in plain words
Butorphanol and Fenfluramine 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.
Butorphanol belongs to Musculoskeletal; Fenfluramine belongs to Central Nervous System.
Why it happens
Probable additive CNS effects; serotonergic activity of fenfluramine may also be relevant, but the interaction is not well established.
What to do
Monitor for sedation, and for serotonin toxicity features such as agitation, tremor and hyperthermia. Reduce the butorphanol dose if drowsiness develops.
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 Butorphanol
- Butorphanol + Olanzapine / samidorphan Contraindicated
- Butorphanol + Sodium oxybate Contraindicated
- Alfentanil + Butorphanol Major
- Alprazolam + Butorphanol Major
- Alvimopan + Butorphanol Major
- Amobarbital + Butorphanol Major
Other interactions of Fenfluramine
- Fenfluramine + Isocarboxazid Contraindicated
- Fenfluramine + Linezolid Contraindicated
- Fenfluramine + Phenelzine Contraindicated
- Fenfluramine + Selegiline Contraindicated
- Fenfluramine + Tranylcypromine Contraindicated
- Almotriptan + Fenfluramine Major
Frequently asked questions
Can I take Butorphanol with Fenfluramine?
MediHelp rates the interaction as moderate. Butorphanol and Fenfluramine 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. Fenfluramine is an antiseizure drug that commonly causes somnolence and fatigue, so it may add to butorphanol sedation instead of opposing it. The effect has not been well characterised.
How serious is the interaction between Butorphanol and Fenfluramine?
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 sedation, and for serotonin toxicity features such as agitation, tremor and hyperthermia. Reduce the butorphanol dose if drowsiness develops.
What other medicines interact with Butorphanol?
MediHelp also lists interactions of Butorphanol with, for example, Olanzapine / samidorphan, Sodium oxybate, Alfentanil. The full list is on the Butorphanol page.
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