Drug interactions
Fentanyl + Fluconazole
Severity: Major
Fentanyl and Fluconazole: 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
Fluconazole is a moderate CYP3A4 inhibitor and can substantially increase fentanyl exposure. Cases of delayed or severe respiratory depression have been reported with this combination.
What this interaction means in plain words
Fentanyl and Fluconazole 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; Fluconazole belongs to Anti Fungals.
Why it happens
Fluconazole inhibits CYP3A4, reducing the metabolic clearance of fentanyl.
What to do
Monitor for respiratory depression and sedation, and reduce the fentanyl dose if the combination is necessary. Continue monitoring after stopping fluconazole as inhibition wanes.
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 Fluconazole
- Dihydroergotamine intranasal + Fluconazole Contraindicated
- Dihydroergotamine + Fluconazole Contraindicated
- Dofetilide + Fluconazole Contraindicated
- Dronedarone + Fluconazole Contraindicated
- Erythromycin + Fluconazole Contraindicated
- Flibanserin + Fluconazole Contraindicated
Frequently asked questions
Can I take Fentanyl with Fluconazole?
MediHelp rates the interaction as major. Fentanyl and Fluconazole 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. Fluconazole is a moderate CYP3A4 inhibitor and can substantially increase fentanyl exposure. Cases of delayed or severe respiratory depression have been reported with this combination.
How serious is the interaction between Fentanyl and Fluconazole?
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 respiratory depression and sedation, and reduce the fentanyl dose if the combination is necessary. Continue monitoring after stopping fluconazole as inhibition wanes.
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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