Drug interactions
Cyclophosphamide + Siponimod
Severity: Major
Cyclophosphamide 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
Siponimod reduces circulating lymphocytes and cyclophosphamide is immunosuppressive, so combined use increases infection risk. The effect may last for weeks after either drug is stopped.
What this interaction means in plain words
Cyclophosphamide 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.
Cyclophosphamide belongs to Oncology; Siponimod belongs to Central Nervous System.
Why it happens
Additive immunosuppression through lymphocyte sequestration and cytotoxic lymphocyte depletion.
What to do
Avoid starting siponimod soon after cyclophosphamide and monitor lymphocyte counts and infections when switching therapies.
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 Cyclophosphamide
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 Cyclophosphamide with Siponimod?
MediHelp rates the interaction as major. Cyclophosphamide 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. Siponimod reduces circulating lymphocytes and cyclophosphamide is immunosuppressive, so combined use increases infection risk. The effect may last for weeks after either drug is stopped.
How serious is the interaction between Cyclophosphamide 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 soon after cyclophosphamide and monitor lymphocyte counts and infections when switching therapies.
What other medicines interact with Cyclophosphamide?
MediHelp also lists interactions of Cyclophosphamide with, for example, Adenovirus types 4 and 7 live, Belatacept, Bendamustine. The full list is on the Cyclophosphamide page.
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