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Drug interactions

Fentanyl intranasal + Posaconazole

Severity: Major

Fentanyl intranasal 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 can substantially raise fentanyl concentrations, because CYP3A4 is its main route of elimination. This can cause profound sedation and potentially fatal respiratory depression.

What this interaction means in plain words

Fentanyl intranasal 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.

Evidence level: High

Why it happens

Strong CYP3A4 inhibition reduces fentanyl clearance.

What to do

Avoid if possible or use an alternative opioid. If unavoidable, monitor for respiratory depression and sedation frequently and adjust the fentanyl 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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Fentanyl intranasal with Posaconazole?

MediHelp rates the interaction as major. Fentanyl intranasal 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 can substantially raise fentanyl concentrations, because CYP3A4 is its main route of elimination. This can cause profound sedation and potentially fatal respiratory depression.

How serious is the interaction between Fentanyl intranasal 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 if possible or use an alternative opioid. If unavoidable, monitor for respiratory depression and sedation frequently and adjust the fentanyl dose.

What other medicines interact with Posaconazole?

MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.

Full monographs, dosing and an interaction checker in the MediHelp app

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