Drug interactions
Fentanyl + Fosaprepitant
Severity: Moderate
Fentanyl and Fosaprepitant: 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
Fosaprepitant, a prodrug of aprepitant, is a moderate CYP3A4 inhibitor and can modestly raise fentanyl exposure. With a single IV dose the effect is usually short-lived but could increase sedation.
What this interaction means in plain words
Fentanyl and Fosaprepitant 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; Fosaprepitant belongs to Gastrointestinal Tract.
Why it happens
Aprepitant moderately inhibits CYP3A4, slowing fentanyl metabolism.
What to do
Monitor for sedation and respiratory depression in the days after fosaprepitant administration. Reduce the fentanyl dose if excess opioid effects appear.
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 Fosaprepitant
- Flibanserin + Fosaprepitant Contraindicated
- Fosaprepitant + Pimozide Contraindicated
- Alprazolam + Fosaprepitant Moderate
- Amiodarone + Fosaprepitant Moderate
- Amobarbital + Fosaprepitant Moderate
- Apalutamide + Fosaprepitant Moderate
Frequently asked questions
Can I take Fentanyl with Fosaprepitant?
MediHelp rates the interaction as moderate. Fentanyl and Fosaprepitant 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. Fosaprepitant, a prodrug of aprepitant, is a moderate CYP3A4 inhibitor and can modestly raise fentanyl exposure. With a single IV dose the effect is usually short-lived but could increase sedation.
How serious is the interaction between Fentanyl and Fosaprepitant?
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 respiratory depression in the days after fosaprepitant administration. Reduce the fentanyl dose if excess opioid effects appear.
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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