Drug interactions
Methylprednisolone + Phenytoin
Severity: Moderate
Methylprednisolone and Phenytoin: 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
Phenytoin induces hepatic enzymes and can lower methylprednisolone exposure, reducing its anti-inflammatory or immunosuppressive effect. Corticosteroids can also alter phenytoin concentrations unpredictably.
What this interaction means in plain words
Methylprednisolone and Phenytoin 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.
Methylprednisolone belongs to Endocrine; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4 and P-glycoprotein, increasing methylprednisolone clearance.
What to do
Monitor clinical response to methylprednisolone and increase the dose if needed. Check phenytoin levels when steroids are started or stopped.
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 Methylprednisolone
- Bcg vaccine live + Methylprednisolone Contraindicated
- Measles mumps and rubella vaccine live + Methylprednisolone Contraindicated
- Measles mumps rubella and varicella vaccine live + Methylprednisolone Contraindicated
- Measles vaccine + Methylprednisolone Contraindicated
- Methylprednisolone + Mifepristone Contraindicated
- Methylprednisolone + Rubella vaccine Contraindicated
Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Frequently asked questions
Can I take Methylprednisolone with Phenytoin?
MediHelp rates the interaction as moderate. Methylprednisolone and Phenytoin 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. Phenytoin induces hepatic enzymes and can lower methylprednisolone exposure, reducing its anti-inflammatory or immunosuppressive effect. Corticosteroids can also alter phenytoin concentrations unpredictably.
How serious is the interaction between Methylprednisolone and Phenytoin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor clinical response to methylprednisolone and increase the dose if needed. Check phenytoin levels when steroids are started or stopped.
What other medicines interact with Methylprednisolone?
MediHelp also lists interactions of Methylprednisolone with, for example, Bcg vaccine live, Measles mumps and rubella vaccine live, Measles mumps rubella and varicella vaccine live. The full list is on the Methylprednisolone page.
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