Drug interactions
Aprepitant + Fentanyl transdermal
Severity: Major
Aprepitant and Fentanyl transdermal: major interaction.
Last updated Sources: UK SmPC
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
Aprepitant can increase fentanyl concentrations by inhibiting CYP3A4. With transdermal patches the effect develops slowly and persists, so respiratory depression and sedation may emerge late.
What this interaction means in plain words
Aprepitant and Fentanyl transdermal can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Aprepitant inhibits CYP3A4, reducing fentanyl clearance.
What to do
Monitor for sedation and respiratory depression over several days and adjust the patch dose as needed. Be vigilant after aprepitant is discontinued as fentanyl levels will fall.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
- Aprepitant 125 mg hard capsules - SmPC sections 4.3/4.5 (names the partner; "alfentanil, diergotamine, ergotamine, fentanyl, and quinidine (see section 4.4)") — electronic medicines compendium (UK SmPC)
Other interactions of Aprepitant
- Aprepitant + Lomitapide Contraindicated
- Aprepitant + Pimozide Contraindicated
- Aprepitant + Avapritinib Major
- Aprepitant + Bosutinib Major
- Aprepitant + Carbamazepine Major
- Aprepitant + Cobicistat Major
Frequently asked questions
Can I take Aprepitant with Fentanyl transdermal?
MediHelp rates the interaction as major. Aprepitant and Fentanyl transdermal can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Aprepitant can increase fentanyl concentrations by inhibiting CYP3A4. With transdermal patches the effect develops slowly and persists, so respiratory depression and sedation may emerge late.
How serious is the interaction between Aprepitant and Fentanyl transdermal?
MediHelp rates it major, 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 over several days and adjust the patch dose as needed. Be vigilant after aprepitant is discontinued as fentanyl levels will fall.
What other medicines interact with Aprepitant?
MediHelp also lists interactions of Aprepitant with, for example, Lomitapide, Pimozide, Avapritinib. The full list is on the Aprepitant page.
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