Drug interactions
Ribociclib + Siponimod
Severity: Major
Ribociclib 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
Ribociclib is a CYP3A4 inhibitor and may raise siponimod exposure. Both drugs also prolong the QT interval, and siponimod can cause bradycardia, so arrhythmia risk is increased.
What this interaction means in plain words
Ribociclib 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.
Ribociclib belongs to Oncology; Siponimod belongs to Central Nervous System.
Why it happens
CYP3A4 inhibition by ribociclib reduces siponimod clearance, combined with additive QT prolongation.
What to do
Avoid the combination where possible. If it is needed, obtain a baseline ECG, correct electrolytes, and monitor ECG and heart rate, particularly in patients with reduced CYP2C9 function.
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 Ribociclib
- Amiodarone + Ribociclib Contraindicated
- Cisapride + Ribociclib Contraindicated
- Dofetilide + Ribociclib Contraindicated
- Dronedarone + Ribociclib Contraindicated
- Flibanserin + Ribociclib Contraindicated
- Ibutilide + Ribociclib Contraindicated
Frequently asked questions
Can I take Ribociclib with Siponimod?
MediHelp rates the interaction as major. Ribociclib 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. Ribociclib is a CYP3A4 inhibitor and may raise siponimod exposure. Both drugs also prolong the QT interval, and siponimod can cause bradycardia, so arrhythmia risk is increased.
How serious is the interaction between Ribociclib 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 where possible. If it is needed, obtain a baseline ECG, correct electrolytes, and monitor ECG and heart rate, particularly in patients with reduced CYP2C9 function.
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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