Drug interactions
Esomeprazole + Fosphenytoin
Severity: Moderate
Esomeprazole and Fosphenytoin: 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
Esomeprazole may raise phenytoin concentrations, as fosphenytoin is converted to phenytoin, and phenytoin may lower esomeprazole levels. Because phenytoin has a narrow therapeutic range, toxicity such as nystagmus, ataxia and confusion may develop.
What this interaction means in plain words
Esomeprazole and Fosphenytoin 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.
Esomeprazole belongs to Gastrointestinal Tract; Fosphenytoin belongs to Central Nervous System.
Why it happens
Esomeprazole inhibits CYP2C19 metabolism of phenytoin, while phenytoin induces CYP3A4 and CYP2C19 metabolism of esomeprazole.
What to do
Monitor serum phenytoin concentrations when starting or stopping esomeprazole and adjust the dose accordingly; also monitor acid control.
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 Esomeprazole
- Esomeprazole + Mavacamten Contraindicated
- Esomeprazole + Rilpivirine Contraindicated
- Acalabrutinib + Esomeprazole Major
- Atazanavir + Esomeprazole Major
- Citalopram + Esomeprazole Major
- Clopidogrel + Esomeprazole Major
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 Esomeprazole with Fosphenytoin?
MediHelp rates the interaction as moderate. Esomeprazole and Fosphenytoin 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. Esomeprazole may raise phenytoin concentrations, as fosphenytoin is converted to phenytoin, and phenytoin may lower esomeprazole levels. Because phenytoin has a narrow therapeutic range, toxicity such as nystagmus, ataxia and confusion may develop.
How serious is the interaction between Esomeprazole and Fosphenytoin?
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 serum phenytoin concentrations when starting or stopping esomeprazole and adjust the dose accordingly; also monitor acid control.
What other medicines interact with Esomeprazole?
MediHelp also lists interactions of Esomeprazole with, for example, Mavacamten, Rilpivirine, Acalabrutinib. The full list is on the Esomeprazole page.
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