Drug interactions
Conivaptan + Siponimod
Severity: Moderate
Conivaptan and Siponimod: moderate 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
Conivaptan is a CYP3A4 inhibitor and may raise siponimod exposure. Siponimod is cleared mainly by CYP2C9 and partly by CYP3A4, so the effect depends on the patient's CYP2C9 genotype. Higher exposure increases the risk of bradycardia, lymphopenia and other dose-related effects.
What this interaction means in plain words
Conivaptan and Siponimod can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Inhibition of CYP3A4-mediated metabolism of siponimod, which is a minor pathway unless CYP2C9 function is reduced.
What to do
Avoid use when the patient also takes a CYP2C9 inhibitor or has a reduced-function CYP2C9 genotype. Otherwise monitor heart rate and lymphocyte counts and keep conivaptan courses short.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Conivaptan with Siponimod?
MediHelp rates the interaction as moderate. Conivaptan and Siponimod can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Conivaptan is a CYP3A4 inhibitor and may raise siponimod exposure. Siponimod is cleared mainly by CYP2C9 and partly by CYP3A4, so the effect depends on the patient's CYP2C9 genotype. Higher exposure increases the risk of bradycardia, lymphopenia and other dose-related effects.
How serious is the interaction between Conivaptan and Siponimod?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid use when the patient also takes a CYP2C9 inhibitor or has a reduced-function CYP2C9 genotype. Otherwise monitor heart rate and lymphocyte counts and keep conivaptan courses short.
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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