Drug interactions
Fenfluramine + Morphine
Severity: Moderate
Fenfluramine and Morphine: 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 increases serotonin release, so with morphine there is a theoretical risk of serotonin syndrome. Fenfluramine can also cause somnolence, which may add to opioid sedation.
What this interaction means in plain words
Fenfluramine and Morphine 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 belongs to Central Nervous System; Morphine belongs to Musculoskeletal.
Why it happens
Possible additive serotonergic activity combined with additive CNS depressant effects.
What to do
Monitor for signs of serotonin syndrome and for excess sedation. Stop the serotonergic agent and treat supportively if toxicity is suspected.
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 Morphine
- Alvimopan + Morphine Contraindicated
- Isocarboxazid + Morphine Contraindicated
- Morphine + Olanzapine / samidorphan Contraindicated
- Morphine + Phenelzine Contraindicated
- Morphine + Tranylcypromine Contraindicated
- Alfentanil + Morphine 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 Fenfluramine with Morphine?
MediHelp rates the interaction as moderate. Fenfluramine and Morphine 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 increases serotonin release, so with morphine there is a theoretical risk of serotonin syndrome. Fenfluramine can also cause somnolence, which may add to opioid sedation.
How serious is the interaction between Fenfluramine and Morphine?
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 signs of serotonin syndrome and for excess sedation. Stop the serotonergic agent and treat supportively if toxicity is suspected.
What other medicines interact with Morphine?
MediHelp also lists interactions of Morphine with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Morphine page.
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