Drug interactions
Everolimus + Fosphenytoin
Severity: Major
Everolimus and Fosphenytoin: major interaction.
Last updated Sources: US FDA label
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 CYP3A4 inducer, and can markedly lower everolimus exposure. This risks loss of efficacy or transplant rejection.
What this interaction means in plain words
Everolimus and Fosphenytoin 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.
Everolimus belongs to Oncology; Fosphenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4 and P-glycoprotein, increasing everolimus clearance.
What to do
Avoid the combination and use a non-inducing anticonvulsant. If it cannot be avoided, increase the everolimus dose and monitor trough concentrations closely.
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 Everolimus
- Bcg vaccine live + Everolimus Contraindicated
- Everolimus + Influenza virus vaccine quadrivalent intranasal Contraindicated
- Everolimus + Levoketoconazole Contraindicated
- Everolimus + Measles mumps and rubella vaccine live Contraindicated
- Everolimus + Measles mumps rubella and varicella vaccine live Contraindicated
- Everolimus + Measles vaccine 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 Everolimus with Fosphenytoin?
MediHelp rates the interaction as major. Everolimus and Fosphenytoin 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. Fosphenytoin is converted to phenytoin, a strong CYP3A4 inducer, and can markedly lower everolimus exposure. This risks loss of efficacy or transplant rejection.
How serious is the interaction between Everolimus and Fosphenytoin?
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-inducing anticonvulsant. If it cannot be avoided, increase the everolimus dose and monitor trough concentrations closely.
What other medicines interact with Everolimus?
MediHelp also lists interactions of Everolimus with, for example, Bcg vaccine live, Influenza virus vaccine quadrivalent intranasal, Levoketoconazole. The full list is on the Everolimus page.
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