Drug interactions
Quinidine + Siponimod
Severity: Major
Quinidine 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 slows heart rate on initiation, and quinidine prolongs the QT interval. Bradycardia combined with QT prolongation increases the risk of torsades de pointes. Siponimod labeling advises against starting it in patients on QT-prolonging drugs with arrhythmogenic potential.
What this interaction means in plain words
Quinidine 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.
Quinidine belongs to Anti Parasitic; Siponimod belongs to Central Nervous System.
Why it happens
Additive pharmacodynamic effect of siponimod-induced bradycardia and quinidine QT prolongation.
What to do
Avoid starting siponimod in patients on quinidine unless the benefit outweighs the risk. If it is considered, obtain cardiology input and monitor the ECG and heart rate at 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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Other interactions of Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine 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 Quinidine with Siponimod?
MediHelp rates the interaction as major. Quinidine 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 slows heart rate on initiation, and quinidine prolongs the QT interval. Bradycardia combined with QT prolongation increases the risk of torsades de pointes. Siponimod labeling advises against starting it in patients on QT-prolonging drugs with arrhythmogenic potential.
How serious is the interaction between Quinidine 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 in patients on quinidine unless the benefit outweighs the risk. If it is considered, obtain cardiology input and monitor the ECG and heart rate at initiation.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine page.
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