Drug interactions
Fentanyl + Tucatinib
Severity: Major
Fentanyl and Tucatinib: 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
Tucatinib inhibits CYP3A4, the main enzyme clearing fentanyl, so fentanyl concentrations can rise. This may cause deep sedation and potentially fatal respiratory depression.
What this interaction means in plain words
Fentanyl and Tucatinib 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; Tucatinib belongs to Oncology.
Why it happens
Tucatinib inhibition of CYP3A4-mediated fentanyl metabolism.
What to do
Avoid the combination if possible; otherwise lower the fentanyl dose and monitor closely for respiratory depression and sedation. Reassess dosing when tucatinib 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 Tucatinib
- Cisapride + Tucatinib Contraindicated
- Eletriptan + Tucatinib Contraindicated
- Ergotamine + Tucatinib Contraindicated
- Flibanserin + Tucatinib Contraindicated
- Ranolazine + Tucatinib Contraindicated
- Amobarbital + Tucatinib Major
Frequently asked questions
Can I take Fentanyl with Tucatinib?
MediHelp rates the interaction as major. Fentanyl and Tucatinib 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. Tucatinib inhibits CYP3A4, the main enzyme clearing fentanyl, so fentanyl concentrations can rise. This may cause deep sedation and potentially fatal respiratory depression.
How serious is the interaction between Fentanyl and Tucatinib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if possible; otherwise lower the fentanyl dose and monitor closely for respiratory depression and sedation. Reassess dosing when tucatinib 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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