Drug interactions
Fentanyl + Posaconazole
Severity: Major
Fentanyl and Posaconazole: 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
Posaconazole is a strong CYP3A4 inhibitor and can substantially raise fentanyl concentrations. This can cause delayed and profound respiratory depression, and fatalities have been reported with other strong CYP3A4 inhibitors.
What this interaction means in plain words
Fentanyl and Posaconazole 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; Posaconazole belongs to Anti Fungals.
Why it happens
Strong inhibition of CYP3A4-mediated fentanyl metabolism.
What to do
Avoid the combination where possible, or reduce the fentanyl dose and monitor closely for respiratory depression and sedation. Continue monitoring for some time after the azole is stopped, since fentanyl levels fall gradually.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Frequently asked questions
Can I take Fentanyl with Posaconazole?
MediHelp rates the interaction as major. Fentanyl and Posaconazole 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. Posaconazole is a strong CYP3A4 inhibitor and can substantially raise fentanyl concentrations. This can cause delayed and profound respiratory depression, and fatalities have been reported with other strong CYP3A4 inhibitors.
How serious is the interaction between Fentanyl and Posaconazole?
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, or reduce the fentanyl dose and monitor closely for respiratory depression and sedation. Continue monitoring for some time after the azole is stopped, since fentanyl levels fall gradually.
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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