Drug interactions
Fentanyl + Pimavanserin
Severity: Moderate
Fentanyl and Pimavanserin: 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
Pimavanserin is a serotonin 5-HT2A inverse agonist and antipsychotic, and fentanyl has weak serotonergic activity. Theoretical risks include serotonin toxicity and added sedation, and pimavanserin prolongs the QT interval modestly. The evidence for harm is limited.
What this interaction means in plain words
Fentanyl and Pimavanserin 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.
Fentanyl belongs to Musculoskeletal; Pimavanserin belongs to Central Nervous System.
Why it happens
Possible additive serotonergic and CNS depressant effects; mechanism not well established.
What to do
Monitor for sedation, mental status changes and signs of serotonin toxicity. Use the lowest effective doses of both drugs.
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 Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
Other interactions of Pimavanserin
- Lefamulin + Pimavanserin Contraindicated
- Pimavanserin + Pimozide Contraindicated
- Pimavanserin + Vandetanib Contraindicated
- Adagrasib + Pimavanserin Major
- Amiodarone + Pimavanserin Major
- Amisulpride + Pimavanserin Major
Frequently asked questions
Can I take Fentanyl with Pimavanserin?
MediHelp rates the interaction as moderate. Fentanyl and Pimavanserin 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. Pimavanserin is a serotonin 5-HT2A inverse agonist and antipsychotic, and fentanyl has weak serotonergic activity. Theoretical risks include serotonin toxicity and added sedation, and pimavanserin prolongs the QT interval modestly. The evidence for harm is limited.
How serious is the interaction between Fentanyl and Pimavanserin?
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, mental status changes and signs of serotonin toxicity. Use the lowest effective doses of both drugs.
What other medicines interact with Fentanyl?
MediHelp also lists interactions of Fentanyl with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Fentanyl page.
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