Drug interactions
Nafcillin + Siponimod
Severity: Moderate
Nafcillin 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
Nafcillin is a CYP3A4 inducer and may lower siponimod exposure, which could reduce its effect on multiple sclerosis disease control. The effect is greater in patients with reduced CYP2C9 activity, who rely more on CYP3A4 for siponimod clearance.
What this interaction means in plain words
Nafcillin 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.
Why it happens
Induction of CYP3A4 increases siponimod metabolism and lowers plasma concentrations.
What to do
Avoid combining with siponimod in patients with CYP2C9*1/*3 or *2/*3 genotypes. In other patients, consider an alternative antibiotic or monitor for loss of efficacy during a prolonged course.
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
Frequently asked questions
Can I take Nafcillin with Siponimod?
MediHelp rates the interaction as moderate. Nafcillin 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. Nafcillin is a CYP3A4 inducer and may lower siponimod exposure, which could reduce its effect on multiple sclerosis disease control. The effect is greater in patients with reduced CYP2C9 activity, who rely more on CYP3A4 for siponimod clearance.
How serious is the interaction between Nafcillin 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: Avoid combining with siponimod in patients with CYP2C9*1/*3 or *2/*3 genotypes. In other patients, consider an alternative antibiotic or monitor for loss of efficacy during a prolonged course.
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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