Drug interactions
Fentanyl + Voriconazole
Severity: Major
Fentanyl and Voriconazole: 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
Voriconazole strongly inhibits CYP3A4 and markedly increases fentanyl exposure. This can result in severe or prolonged respiratory depression and sedation.
What this interaction means in plain words
Fentanyl and Voriconazole 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; Voriconazole belongs to Anti Fungals.
Why it happens
Strong CYP3A4 inhibition by voriconazole decreases fentanyl metabolism.
What to do
Reduce fentanyl dose and monitor closely for respiratory depression for an extended period. If voriconazole is stopped, watch for reduced opioid effect and adjust the dose.
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 Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
Frequently asked questions
Can I take Fentanyl with Voriconazole?
MediHelp rates the interaction as major. Fentanyl and Voriconazole 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. Voriconazole strongly inhibits CYP3A4 and markedly increases fentanyl exposure. This can result in severe or prolonged respiratory depression and sedation.
How serious is the interaction between Fentanyl and Voriconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce fentanyl dose and monitor closely for respiratory depression for an extended period. If voriconazole is stopped, watch for reduced opioid effect and adjust the dose.
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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