Drug interactions
Erythromycin + Siponimod
Severity: Major
Erythromycin 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
Erythromycin may raise siponimod exposure and both agents can affect cardiac conduction and QT interval, increasing the risk of bradyarrhythmia and QT-related events. Patients with CYP2C9 variants have greater baseline exposure and higher risk.
What this interaction means in plain words
Erythromycin 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.
Erythromycin belongs to Anti Bacterial; Siponimod belongs to Central Nervous System.
Why it happens
CYP3A4 inhibition by erythromycin reduces siponimod clearance, with additive QT effects.
What to do
Avoid the combination and use a non-macrolide antibiotic. If it is necessary, monitor heart rate and ECG and review CYP2C9 genotype or other inhibitors.
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 Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin 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 Erythromycin with Siponimod?
MediHelp rates the interaction as major. Erythromycin 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. Erythromycin may raise siponimod exposure and both agents can affect cardiac conduction and QT interval, increasing the risk of bradyarrhythmia and QT-related events. Patients with CYP2C9 variants have greater baseline exposure and higher risk.
How serious is the interaction between Erythromycin 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 the combination and use a non-macrolide antibiotic. If it is necessary, monitor heart rate and ECG and review CYP2C9 genotype or other inhibitors.
What other medicines interact with Erythromycin?
MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.
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