Drug interactions
Mifepristone + Siponimod
Severity: Major
Mifepristone and Siponimod: 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
Mifepristone is a strong CYP3A4 inhibitor and may raise siponimod concentrations, especially in CYP2C9 poor metabolizers. It also prolongs the QT interval, which adds to siponimod's bradycardic effects.
What this interaction means in plain words
Mifepristone and Siponimod 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; Siponimod belongs to Central Nervous System.
Why it happens
Mifepristone inhibits CYP3A4, and both drugs add to QT prolongation and bradycardia.
What to do
Avoid the combination, particularly in patients with CYP2C9*1/*3 or *2/*3 genotype. If it cannot be avoided, monitor ECG and heart rate.
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 Siponimod
- Cladribine + Siponimod Contraindicated
- Fingolimod + Siponimod Contraindicated
- Fluconazole + Siponimod Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Siponimod Contraindicated
- Ponesimod + Siponimod Contraindicated
- Siponimod + Thioridazine Contraindicated
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 Mifepristone with Siponimod?
MediHelp rates the interaction as major. Mifepristone and Siponimod 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 may raise siponimod concentrations, especially in CYP2C9 poor metabolizers. It also prolongs the QT interval, which adds to siponimod's bradycardic effects.
How serious is the interaction between Mifepristone and Siponimod?
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, particularly in patients with CYP2C9*1/*3 or *2/*3 genotype. If it cannot be avoided, monitor ECG and heart rate.
What other medicines interact with Siponimod?
MediHelp also lists interactions of Siponimod with, for example, Cladribine, Fingolimod, Fluconazole. The full list is on the Siponimod page.
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