Drug interactions
Flecainide + Siponimod
Severity: Major
Flecainide and Siponimod: major interaction.
Last updated Sources: Health Canada product monograph
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 causes bradycardia and AV conduction delay when started, and flecainide slows conduction and may be proarrhythmic. Combined use may increase the risk of bradyarrhythmia and conduction block.
What this interaction means in plain words
Flecainide 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.
Flecainide belongs to Cardiovascular; Siponimod belongs to Central Nervous System.
Why it happens
Additive negative chronotropic and dromotropic effects.
What to do
Seek cardiology advice before starting siponimod in patients on flecainide. If used, monitor heart rate and ECG during initiation.
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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References
Other interactions of Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir 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 Flecainide with Siponimod?
MediHelp rates the interaction as major. Flecainide 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 causes bradycardia and AV conduction delay when started, and flecainide slows conduction and may be proarrhythmic. Combined use may increase the risk of bradyarrhythmia and conduction block.
How serious is the interaction between Flecainide 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: Seek cardiology advice before starting siponimod in patients on flecainide. If used, monitor heart rate and ECG during initiation.
What other medicines interact with Flecainide?
MediHelp also lists interactions of Flecainide with, for example, Nirmatrelvir, Nirmatrelvir / ritonavir, Pimozide. The full list is on the Flecainide page.
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