Drug interactions
Fluvoxamine + Siponimod
Severity: Major
Fluvoxamine 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 is metabolized by CYP2C9 and CYP3A4, and fluvoxamine inhibits CYP2C9 and CYP3A4 to a moderate degree and CYP2C19 strongly, so siponimod exposure may rise. Siponimod also slows heart rate and conduction, and fluvoxamine can affect QT, which adds to the cardiac risk.
What this interaction means in plain words
Fluvoxamine 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.
Fluvoxamine belongs to Central Nervous System; Siponimod belongs to Central Nervous System.
Why it happens
Combined inhibition of CYP2C9 and CYP3A4 reduces siponimod clearance, with additive cardiac conduction and repolarization effects.
What to do
Avoid combining siponimod with drugs that inhibit both CYP2C9 and CYP3A4, and choose a different antidepressant if possible. If unavoidable, check the patient's CYP2C9 genotype, obtain an ECG and monitor heart rate.
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 Fluvoxamine
- Agomelatine + Fluvoxamine Contraindicated
- Alosetron + Fluvoxamine Contraindicated
- Fezolinetant + Fluvoxamine Contraindicated
- Fluvoxamine + Isocarboxazid Contraindicated
- Fluvoxamine + Mavacamten Contraindicated
- Fluvoxamine + Methylene blue 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 Fluvoxamine with Siponimod?
MediHelp rates the interaction as major. Fluvoxamine 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 is metabolized by CYP2C9 and CYP3A4, and fluvoxamine inhibits CYP2C9 and CYP3A4 to a moderate degree and CYP2C19 strongly, so siponimod exposure may rise. Siponimod also slows heart rate and conduction, and fluvoxamine can affect QT, which adds to the cardiac risk.
How serious is the interaction between Fluvoxamine 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 combining siponimod with drugs that inhibit both CYP2C9 and CYP3A4, and choose a different antidepressant if possible. If unavoidable, check the patient's CYP2C9 genotype, obtain an ECG and monitor heart rate.
What other medicines interact with Fluvoxamine?
MediHelp also lists interactions of Fluvoxamine with, for example, Agomelatine, Alosetron, Fezolinetant. The full list is on the Fluvoxamine page.
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