Drug interactions
Esketamine + Phenytoin
Severity: Moderate
Esketamine 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 can cause drowsiness, dizziness and ataxia, particularly at higher levels, and these effects may add to those of esketamine. Phenytoin is also a CYP3A4 and CYP2B6 inducer that may lower esketamine exposure.
What this interaction means in plain words
Esketamine 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.
Esketamine belongs to Central Nervous System; Phenytoin belongs to Central Nervous System.
Why it happens
Additive CNS depression, and enzyme induction by phenytoin that may reduce esketamine levels.
What to do
Monitor sedation and treatment response during the combined use. Check phenytoin levels if ataxia or excessive drowsiness occurs.
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 Esketamine
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 Esketamine with Phenytoin?
MediHelp rates the interaction as moderate. Esketamine 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 can cause drowsiness, dizziness and ataxia, particularly at higher levels, and these effects may add to those of esketamine. Phenytoin is also a CYP3A4 and CYP2B6 inducer that may lower esketamine exposure.
How serious is the interaction between Esketamine 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 sedation and treatment response during the combined use. Check phenytoin levels if ataxia or excessive drowsiness occurs.
What other medicines interact with Esketamine?
MediHelp also lists interactions of Esketamine with, for example, Alfentanil, Amobarbital, Belladonna and opium. The full list is on the Esketamine page.
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