Drug interactions
Leflunomide + Siponimod
Severity: Major
Leflunomide 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
Both drugs reduce immune function, and leflunomide's active metabolite persists for a long time after the last dose. Together they may add to the risk of serious infection, including after one agent is stopped.
What this interaction means in plain words
Leflunomide 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.
Leflunomide belongs to Musculoskeletal; Siponimod belongs to Central Nervous System.
Why it happens
Additive immunosuppression: siponimod sequesters lymphocytes in lymph nodes while leflunomide inhibits pyrimidine synthesis in proliferating lymphocytes.
What to do
Avoid starting siponimod while leflunomide is still active unless the benefit is clear; consider an accelerated elimination procedure for leflunomide when switching. Monitor lymphocyte counts and watch closely for infection.
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 Leflunomide
- Bcg vaccine live + Leflunomide Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Leflunomide Contraindicated
- Leflunomide + Measles mumps and rubella vaccine live Contraindicated
- Leflunomide + Measles mumps rubella and varicella vaccine live Contraindicated
- Leflunomide + Measles vaccine Contraindicated
- Leflunomide + Smallpox vaccine live Contraindicated
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 Leflunomide with Siponimod?
MediHelp rates the interaction as major. Leflunomide 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. Both drugs reduce immune function, and leflunomide's active metabolite persists for a long time after the last dose. Together they may add to the risk of serious infection, including after one agent is stopped.
How serious is the interaction between Leflunomide 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 leflunomide is still active unless the benefit is clear; consider an accelerated elimination procedure for leflunomide when switching. Monitor lymphocyte counts and watch closely for infection.
What other medicines interact with Leflunomide?
MediHelp also lists interactions of Leflunomide with, for example, Bcg vaccine live, Influenza virus vaccine quadrivalent intranasal, Measles mumps and rubella vaccine live. The full list is on the Leflunomide page.
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