Drug interactions
Ketoconazole + Siponimod
Severity: Major
Ketoconazole 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
Ketoconazole inhibits CYP3A4, and siponimod is metabolized by CYP2C9 and CYP3A4, so exposure may increase. Labeling advises against siponimod with drugs that combine moderate CYP2C9 and moderate or strong CYP3A4 inhibition, with a risk of bradyarrhythmia and other adverse effects.
What this interaction means in plain words
Ketoconazole 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.
Ketoconazole belongs to Anti Fungals; Siponimod belongs to Central Nervous System.
Why it happens
CYP3A4 inhibition by ketoconazole reduces siponimod clearance, especially with reduced CYP2C9 function.
What to do
Check the patient's CYP2C9 genotype and avoid the combination if the patient is a CYP2C9*2/*3 or similar carrier. Otherwise consider an alternative antifungal and monitor heart rate and adverse effects.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole 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 Ketoconazole with Siponimod?
MediHelp rates the interaction as major. Ketoconazole 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. Ketoconazole inhibits CYP3A4, and siponimod is metabolized by CYP2C9 and CYP3A4, so exposure may increase. Labeling advises against siponimod with drugs that combine moderate CYP2C9 and moderate or strong CYP3A4 inhibition, with a risk of bradyarrhythmia and other adverse effects.
How serious is the interaction between Ketoconazole 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: Check the patient's CYP2C9 genotype and avoid the combination if the patient is a CYP2C9*2/*3 or similar carrier. Otherwise consider an alternative antifungal and monitor heart rate and adverse effects.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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