Drug interactions
Fentanyl + Itraconazole
Severity: Major
Fentanyl and Itraconazole: 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
Itraconazole is a strong CYP3A4 inhibitor and markedly increases fentanyl exposure. This can cause severe or fatal respiratory depression, which may be prolonged because inhibition persists after itraconazole is stopped.
What this interaction means in plain words
Fentanyl and Itraconazole 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; Itraconazole belongs to Anti Fungals.
Why it happens
Strong inhibition of CYP3A4 and intestinal metabolism greatly reduces fentanyl clearance.
What to do
Avoid the combination where possible, including for about two weeks after itraconazole is stopped. If unavoidable, reduce the fentanyl dose and monitor closely 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 Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
Other interactions of Itraconazole
- Alfuzosin + Itraconazole Contraindicated
- Alprazolam + Itraconazole Contraindicated
- Avanafil + Itraconazole Contraindicated
- Conivaptan + Itraconazole Contraindicated
- Dihydroergotamine intranasal + Itraconazole Contraindicated
- Dihydroergotamine + Itraconazole Contraindicated
Frequently asked questions
Can I take Fentanyl with Itraconazole?
MediHelp rates the interaction as major. Fentanyl and Itraconazole 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. Itraconazole is a strong CYP3A4 inhibitor and markedly increases fentanyl exposure. This can cause severe or fatal respiratory depression, which may be prolonged because inhibition persists after itraconazole is stopped.
How serious is the interaction between Fentanyl and Itraconazole?
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 where possible, including for about two weeks after itraconazole is stopped. If unavoidable, reduce the fentanyl dose and monitor closely for respiratory depression and sedation.
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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