Drug interactions
Ibritumomab tiuxetan + Siponimod
Severity: Major
Ibritumomab tiuxetan 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
Ibritumomab tiuxetan delivers radioimmunotherapy that causes prolonged, severe cytopenias. Siponimod additionally lowers lymphocytes, which may increase the risk of serious infection.
What this interaction means in plain words
Ibritumomab tiuxetan 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.
Why it happens
Additive immunosuppression from radiation-induced marrow suppression and S1P-receptor-mediated lymphocyte sequestration.
What to do
Avoid starting siponimod while marrow suppression persists, and monitor blood counts frequently. Consider interrupting siponimod during treatment.
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
Frequently asked questions
Can I take Ibritumomab tiuxetan with Siponimod?
MediHelp rates the interaction as major. Ibritumomab tiuxetan 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. Ibritumomab tiuxetan delivers radioimmunotherapy that causes prolonged, severe cytopenias. Siponimod additionally lowers lymphocytes, which may increase the risk of serious infection.
How serious is the interaction between Ibritumomab tiuxetan 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 starting siponimod while marrow suppression persists, and monitor blood counts frequently. Consider interrupting siponimod during treatment.
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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