Drug interactions
Esomeprazole + Phenytoin
Severity: Moderate
Esomeprazole 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
Esomeprazole can raise phenytoin concentrations by inhibiting CYP2C19, a secondary route of phenytoin metabolism. Because phenytoin has a narrow therapeutic window and saturable kinetics, even modest increases can lead to nystagmus, ataxia or confusion.
What this interaction means in plain words
Esomeprazole 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.
Esomeprazole belongs to Gastrointestinal Tract; Phenytoin belongs to Central Nervous System.
Why it happens
Esomeprazole inhibits CYP2C19-mediated phenytoin metabolism, reducing its clearance.
What to do
Monitor serum phenytoin concentrations and for signs of toxicity when starting or stopping esomeprazole. Adjust the phenytoin dose according to levels.
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 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 Esomeprazole with Phenytoin?
MediHelp rates the interaction as moderate. Esomeprazole 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. Esomeprazole can raise phenytoin concentrations by inhibiting CYP2C19, a secondary route of phenytoin metabolism. Because phenytoin has a narrow therapeutic window and saturable kinetics, even modest increases can lead to nystagmus, ataxia or confusion.
How serious is the interaction between Esomeprazole 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 serum phenytoin concentrations and for signs of toxicity when starting or stopping esomeprazole. Adjust the phenytoin dose according to levels.
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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