Drug interactions
Fosphenytoin + Prednisolone
Severity: Moderate
Fosphenytoin and Prednisolone: 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
Fosphenytoin is converted to phenytoin, a strong inducer of hepatic enzymes, and it can speed up the clearance of prednisolone. Steroid exposure falls, which may lead to loss of anti-inflammatory or immunosuppressive control, for example in asthma, transplant or autoimmune disease.
What this interaction means in plain words
Fosphenytoin and Prednisolone 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.
Fosphenytoin belongs to Central Nervous System; Prednisolone belongs to Endocrine.
Why it happens
Phenytoin induces CYP3A4 and possibly P-glycoprotein, increasing the metabolism and efflux of prednisolone.
What to do
Monitor clinical response to prednisolone and increase the dose if disease control worsens. Reassess the steroid dose when the anticonvulsant is stopped or changed.
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 Prednisolone
- Bcg vaccine live + Prednisolone Contraindicated
- Measles mumps and rubella vaccine live + Prednisolone Contraindicated
- Measles mumps rubella and varicella vaccine live + Prednisolone Contraindicated
- Measles vaccine + Prednisolone Contraindicated
- Mifepristone + Prednisolone Contraindicated
- Prednisolone + Radium-223 dichloride Contraindicated
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Fosphenytoin with Prednisolone?
MediHelp rates the interaction as moderate. Fosphenytoin and Prednisolone 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. Fosphenytoin is converted to phenytoin, a strong inducer of hepatic enzymes, and it can speed up the clearance of prednisolone. Steroid exposure falls, which may lead to loss of anti-inflammatory or immunosuppressive control, for example in asthma, transplant or autoimmune disease.
How serious is the interaction between Fosphenytoin and Prednisolone?
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 prednisolone and increase the dose if disease control worsens. Reassess the steroid dose when the anticonvulsant is stopped or changed.
What other medicines interact with Prednisolone?
MediHelp also lists interactions of Prednisolone 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 Prednisolone page.
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