Cenobamate and Phenytoin Interaction
Drug interaction information between Cenobamate and Phenytoin.
Cenobamate and Phenytoin have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Cenobamate and Phenytoin. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Cenobamate slows down the body's ability to clear phenytoin, which can cause the drug to build up to dangerous levels. This can lead to a two-fold increase in the amount of phenytoin in your blood.
FDA Label Information
7 DRUG INTERACTIONS Phenytoin: Gradually decrease phenytoin dosage by up to 50%. carbamazepine ↓ plasma concentrations phenytoin ↑ plasma concentrations Because of a potential 2-fold increase in phenytoin levels, gradually decrease phenytoin dosage by up to 50% as XCOPRI is being titrated.
Cenobamate Also Interacts With
- Phenobarbital moderate
- Clobazam moderate
- Lamotrigine minor
- Carbamazepine minor
Phenytoin Also Interacts With
- Nirmatrelvir/Ritonavir major
- Posaconazole major
- Ranolazine major
- Voriconazole major
- Apixaban moderate
Frequently Asked Questions
What SPL severity band is on file for Cenobamate + Phenytoin?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Phenytoin has 147 labeled pairs on file vs Cenobamate's 5. In the minor band specifically: Cenobamate has 3 (also Lamotrigine, Carbamazepine); Phenytoin has 120 (also Atorvastatin, Omeprazole, Simvastatin, Methylphenidate).
What mechanism field is on file for Cenobamate and Phenytoin?
Cenobamate slows down the body's ability to clear phenytoin, which can cause the drug to build up to dangerous levels. This can lead to a two-fold increase in the amount of phenytoin in your blood.
Phenytoin carries more major-labeled pairs than Cenobamate
SPL source-record counts only. This page's band is minor · classes on file: Cenobamate (Anticonvulsant); Phenytoin (Anticonvulsant (Hydantoin)).
Phenytoin has 4 major-labeled pairs vs Cenobamate's 0. This page itself is in the minor band, not the major band.
0 major · 2 moderate · 3 minor · 5 total
- Other minor peers for Cenobamate
- Lamotrigine
- Carbamazepine
4 major · 23 moderate · 120 minor · 147 total
- Other minor peers for Phenytoin
- Atorvastatin
- Omeprazole
- Simvastatin
- Methylphenidate
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.