Drug interactions
Fentanyl + Lonafarnib
Severity: Major
Fentanyl and Lonafarnib: 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
Fentanyl is not a recognized inhibitor of CYP3A4, so a meaningful rise in lonafarnib exposure from it is not established. The legacy concern is largely unsupported, while lonafarnib itself is a strong CYP3A inhibitor that may increase fentanyl exposure.
What this interaction means in plain words
Fentanyl and Lonafarnib 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; Lonafarnib belongs to Miscellaneous.
Why it happens
Lonafarnib inhibits CYP3A4, which may reduce fentanyl clearance.
What to do
Monitor for sedation and respiratory depression and reduce the fentanyl dose if needed. Reassess when lonafarnib is stopped.
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 Lonafarnib
- Alfuzosin + Lonafarnib Contraindicated
- Amobarbital + Lonafarnib Contraindicated
- Apalutamide + Lonafarnib Contraindicated
- Bosentan + Lonafarnib Contraindicated
- Carbamazepine + Lonafarnib Contraindicated
- Clarithromycin + Lonafarnib Contraindicated
Frequently asked questions
Can I take Fentanyl with Lonafarnib?
MediHelp rates the interaction as major. Fentanyl and Lonafarnib 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 is not a recognized inhibitor of CYP3A4, so a meaningful rise in lonafarnib exposure from it is not established. The legacy concern is largely unsupported, while lonafarnib itself is a strong CYP3A inhibitor that may increase fentanyl exposure.
How serious is the interaction between Fentanyl and Lonafarnib?
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 and reduce the fentanyl dose if needed. Reassess when lonafarnib is stopped.
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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