Drug interactions
Fentanyl + Lenacapavir
Severity: Major
Fentanyl and Lenacapavir: major 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
Lenacapavir is a moderate CYP3A inhibitor and can raise fentanyl concentrations, increasing the risk of oversedation and potentially fatal respiratory depression. The effect may be prolonged because of lenacapavir's long half-life.
What this interaction means in plain words
Fentanyl and Lenacapavir 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.
Fentanyl belongs to Musculoskeletal; Lenacapavir belongs to Anti Virals.
Why it happens
Inhibition of CYP3A4 reduces fentanyl clearance.
What to do
Monitor closely for respiratory depression and sedation and consider lowering the fentanyl dose. Maintain monitoring after lenacapavir is stopped, since inhibition persists.
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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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 Lenacapavir
- Apalutamide + Lenacapavir Contraindicated
- Carbamazepine + Lenacapavir Contraindicated
- Enzalutamide + Lenacapavir Contraindicated
- Flibanserin + Lenacapavir Contraindicated
- Lenacapavir + Phenytoin Contraindicated
- Lenacapavir + Rifampicin Contraindicated
Frequently asked questions
Can I take Fentanyl with Lenacapavir?
MediHelp rates the interaction as major. Fentanyl and Lenacapavir 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. Lenacapavir is a moderate CYP3A inhibitor and can raise fentanyl concentrations, increasing the risk of oversedation and potentially fatal respiratory depression. The effect may be prolonged because of lenacapavir's long half-life.
How serious is the interaction between Fentanyl and Lenacapavir?
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 closely for respiratory depression and sedation and consider lowering the fentanyl dose. Maintain monitoring after lenacapavir is stopped, since inhibition persists.
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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