Drug interactions
Ethanol + Phenytoin
Severity: Moderate
Ethanol 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
Acute alcohol intake can raise phenytoin levels, increasing the risk of toxicity such as ataxia and nystagmus. Chronic heavy drinking can lower phenytoin levels and reduce seizure control, and alcohol itself lowers the seizure threshold.
What this interaction means in plain words
Ethanol 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.
Why it happens
Acute alcohol inhibits phenytoin metabolism, while chronic alcohol induces hepatic CYP enzymes.
What to do
Advise patients to avoid alcohol. Monitor phenytoin levels and clinical status when alcohol use pattern changes.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Ethanol and Phenytoin, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
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 Ethanol with Phenytoin?
MediHelp rates the interaction as moderate. Ethanol 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. Acute alcohol intake can raise phenytoin levels, increasing the risk of toxicity such as ataxia and nystagmus. Chronic heavy drinking can lower phenytoin levels and reduce seizure control, and alcohol itself lowers the seizure threshold.
How serious is the interaction between Ethanol 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: Advise patients to avoid alcohol. Monitor phenytoin levels and clinical status when alcohol use pattern changes.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
