Drug interactions
Fentanyl transmucosal + Voriconazole
Severity: Major
Fentanyl transmucosal 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 inhibits CYP3A4 and can increase systemic fentanyl exposure from the swallowed fraction and the absorbed dose. This raises the risk of excessive sedation and life-threatening respiratory depression.
What this interaction means in plain words
Fentanyl transmucosal 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.
Why it happens
Voriconazole inhibits CYP3A4-mediated metabolism of fentanyl, reducing its clearance and increasing bioavailability.
What to do
Avoid concomitant use where possible. If unavoidable, reduce the fentanyl dose, retitrate cautiously and monitor frequently for respiratory depression and sedation.
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 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 transmucosal with Voriconazole?
MediHelp rates the interaction as major. Fentanyl transmucosal 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 inhibits CYP3A4 and can increase systemic fentanyl exposure from the swallowed fraction and the absorbed dose. This raises the risk of excessive sedation and life-threatening respiratory depression.
How serious is the interaction between Fentanyl transmucosal 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: Avoid concomitant use where possible. If unavoidable, reduce the fentanyl dose, retitrate cautiously and monitor frequently for respiratory depression and sedation.
What other medicines interact with Voriconazole?
MediHelp also lists interactions of Voriconazole with, for example, Avanafil, Butabarbital, Carbamazepine. The full list is on the Voriconazole page.
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