Drug interactions
Fentanyl transdermal + Mifepristone
Severity: Major
Fentanyl transdermal and Mifepristone: 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
Transdermal fentanyl is cleared by CYP3A4, and inhibition can increase systemic exposure over a prolonged period because of the skin depot. This raises the risk of delayed and prolonged respiratory depression.
What this interaction means in plain words
Fentanyl transdermal and Mifepristone 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
Mifepristone inhibits CYP3A4, decreasing fentanyl clearance.
What to do
Avoid if possible; otherwise monitor closely for respiratory depression and sedation and reduce the dose as needed. Continue monitoring after either drug is stopped because effects persist.
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 Mifepristone
- Apixaban + Mifepristone Contraindicated
- Argatroban + Mifepristone Contraindicated
- Cisapride + Mifepristone Contraindicated
- Cortisone + Mifepristone Contraindicated
- Cyclosporin + Mifepristone Contraindicated
- Dabigatran etexilate + Mifepristone Contraindicated
Frequently asked questions
Can I take Fentanyl transdermal with Mifepristone?
MediHelp rates the interaction as major. Fentanyl transdermal and Mifepristone 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. Transdermal fentanyl is cleared by CYP3A4, and inhibition can increase systemic exposure over a prolonged period because of the skin depot. This raises the risk of delayed and prolonged respiratory depression.
How serious is the interaction between Fentanyl transdermal and Mifepristone?
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; otherwise monitor closely for respiratory depression and sedation and reduce the dose as needed. Continue monitoring after either drug is stopped because effects persist.
What other medicines interact with Mifepristone?
MediHelp also lists interactions of Mifepristone with, for example, Apixaban, Argatroban, Cisapride. The full list is on the Mifepristone page.
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