Drug interactions
Cenobamate + Phenytoin
Severity: Major
Cenobamate and Phenytoin: 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
Cenobamate inhibits CYP2C19 and raises phenytoin exposure substantially, which can lead to phenytoin toxicity such as ataxia, nystagmus and confusion. Cenobamate exposure may also be reduced by phenytoin.
What this interaction means in plain words
Cenobamate and Phenytoin 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.
Cenobamate belongs to Central Nervous System; Phenytoin belongs to Central Nervous System.
Why it happens
Cenobamate inhibits CYP2C19, reducing phenytoin metabolism.
What to do
Reduce the phenytoin dose when starting cenobamate, as labeling advises, and monitor phenytoin concentrations and signs of toxicity.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Cenobamate 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.
References
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
Other interactions of Cenobamate
Frequently asked questions
Can I take Cenobamate with Phenytoin?
MediHelp rates the interaction as major. Cenobamate and Phenytoin 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. Cenobamate inhibits CYP2C19 and raises phenytoin exposure substantially, which can lead to phenytoin toxicity such as ataxia, nystagmus and confusion. Cenobamate exposure may also be reduced by phenytoin.
How serious is the interaction between Cenobamate and Phenytoin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce the phenytoin dose when starting cenobamate, as labeling advises, and monitor phenytoin concentrations and signs of toxicity.
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.
