Drug interactions
Irinotecan + Mifepristone
Severity: Major
Irinotecan and Mifepristone: major interaction.
Last updated Sources: Base de donnees publique des medicaments (France)
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 inhibits CYP3A4, the enzyme that converts irinotecan and its active metabolite SN-38 to less active products. Higher exposure may intensify neutropenia and severe diarrhea. The effect may persist for days after mifepristone is stopped because of its long half-life.
What this interaction means in plain words
Irinotecan 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.
Irinotecan belongs to Oncology; Mifepristone belongs to Endocrine.
Why it happens
Mifepristone inhibits CYP3A4-mediated clearance of irinotecan and SN-38, raising systemic exposure.
What to do
Avoid combining them and allow about a week after the last mifepristone dose before starting irinotecan unless there is no alternative. If unavoidable, monitor blood counts and diarrhea closely and reduce the irinotecan dose as needed.
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 Irinotecan
- Clozapine + Irinotecan Contraindicated
- Irinotecan + Sacituzumab govitecan Contraindicated
- Adenovirus types 4 and 7 live + Irinotecan Major
- Apalutamide + Irinotecan Major
- Atazanavir + Irinotecan Major
- Carbamazepine + Irinotecan Major
Frequently asked questions
Can I take Irinotecan with Mifepristone?
MediHelp rates the interaction as major. Irinotecan 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. Mifepristone inhibits CYP3A4, the enzyme that converts irinotecan and its active metabolite SN-38 to less active products. Higher exposure may intensify neutropenia and severe diarrhea. The effect may persist for days after mifepristone is stopped because of its long half-life.
How serious is the interaction between Irinotecan 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 combining them and allow about a week after the last mifepristone dose before starting irinotecan unless there is no alternative. If unavoidable, monitor blood counts and diarrhea closely and reduce the irinotecan dose as needed.
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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