Drug interactions
Doxepin + Siponimod
Severity: Moderate
Doxepin 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
Doxepin, a tricyclic antidepressant, can prolong the QT interval and slow conduction, and siponimod can cause bradycardia on initiation. The combination may raise the risk of arrhythmia, especially with bradycardia or electrolyte disturbances.
What this interaction means in plain words
Doxepin 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.
Doxepin belongs to Dermatology; Siponimod belongs to Central Nervous System.
Why it happens
Additive cardiac effects: QT prolongation from doxepin and heart rate slowing from siponimod.
What to do
Obtain a baseline ECG before starting siponimod and seek cardiology advice if QTc is prolonged. Monitor heart rate and QTc and correct potassium and magnesium.
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
Other interactions of Doxepin
- Doxepin + Isocarboxazid Contraindicated
- Doxepin + Phenelzine Contraindicated
- Doxepin + Procarbazine Contraindicated
- Doxepin + Safinamide Contraindicated
- Doxepin + Selegiline Contraindicated
- Doxepin + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Doxepin with Siponimod?
MediHelp rates the interaction as moderate. Doxepin 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. Doxepin, a tricyclic antidepressant, can prolong the QT interval and slow conduction, and siponimod can cause bradycardia on initiation. The combination may raise the risk of arrhythmia, especially with bradycardia or electrolyte disturbances.
How serious is the interaction between Doxepin 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: Obtain a baseline ECG before starting siponimod and seek cardiology advice if QTc is prolonged. Monitor heart rate and QTc and correct potassium and magnesium.
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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