Drug interactions
Mifepristone + Sirolimus
Severity: Major
Mifepristone and Sirolimus: major interaction.
Last updated Sources: US FDA label
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
Mifepristone is a strong CYP3A4 inhibitor, and sirolimus is a sensitive CYP3A4 and P-gp substrate with a narrow therapeutic index. Co-administration can substantially raise sirolimus concentrations, increasing the risk of immunosuppressive toxicity, hyperlipidemia, myelosuppression and nephrotoxicity.
What this interaction means in plain words
Mifepristone and Sirolimus 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.
Mifepristone belongs to Endocrine; Sirolimus belongs to Miscellaneous.
Why it happens
Mifepristone inhibits CYP3A4 (and possibly P-gp), reducing sirolimus clearance.
What to do
Avoid the combination where possible, as mifepristone labeling warns against use with narrow-index CYP3A substrates. If unavoidable, reduce the sirolimus dose and monitor trough levels closely, including after mifepristone is stopped.
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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References
Other interactions of Mifepristone
- Apixaban + Mifepristone Contraindicated
- Argatroban + Mifepristone Contraindicated
- Cisapride + Mifepristone Contraindicated
- Cortisone + Mifepristone Contraindicated
- Cyclosporin + Mifepristone Contraindicated
- Dabigatran etexilate + Mifepristone Contraindicated
Other interactions of Sirolimus
- Adenovirus types 4 and 7 live + Sirolimus Contraindicated
- Bcg vaccine live + Sirolimus Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Sirolimus Contraindicated
- Ketoconazole + Sirolimus Contraindicated
- Levoketoconazole + Sirolimus Contraindicated
- Measles mumps and rubella vaccine live + Sirolimus Contraindicated
Frequently asked questions
Can I take Mifepristone with Sirolimus?
MediHelp rates the interaction as major. Mifepristone and Sirolimus 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. Mifepristone is a strong CYP3A4 inhibitor, and sirolimus is a sensitive CYP3A4 and P-gp substrate with a narrow therapeutic index. Co-administration can substantially raise sirolimus concentrations, increasing the risk of immunosuppressive toxicity, hyperlipidemia, myelosuppression and nephrotoxicity.
How serious is the interaction between Mifepristone and Sirolimus?
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, as mifepristone labeling warns against use with narrow-index CYP3A substrates. If unavoidable, reduce the sirolimus dose and monitor trough levels closely, including after mifepristone is stopped.
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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