Phenobarbital and Cenobamate Interaction
Drug interaction information between Phenobarbital and Cenobamate.
Phenobarbital and Cenobamate have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Phenobarbital and Cenobamate. 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 causes the levels of phenobarbital in your blood to go up. This makes it more likely that you will have a bad reaction to the phenobarbital.
FDA Label Information
( 7.1 ) Phenobarbital and Clobazam: Reduce dosage as needed when used concomitantly with XCOPRI. phenobarbital ↑ plasma concentrations Because of a potential for an increase in the risk of adverse reactions from these drugs, consider a reduction in dosage of phenobarbital or clobazam, as clinically appropriate, when used concomitantly with XCOPRI.
Phenobarbital Also Interacts With
- Nirmatrelvir/Ritonavir major
- Ranolazine major
- Voriconazole major
- Canagliflozin moderate
- Clarithromycin moderate
Cenobamate Also Interacts With
- Clobazam moderate
- Lamotrigine minor
- Carbamazepine minor
- Phenytoin minor
Frequently Asked Questions
What SPL severity band is on file for Phenobarbital + Cenobamate?
Compiled FDA labeling labels this pair moderate. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Phenobarbital has 59 labeled pairs on file vs Cenobamate's 5. In the moderate band specifically: Phenobarbital has 13 (also Canagliflozin, Clarithromycin, Dapsone Topical, Dolutegravir/Lamivudine); Cenobamate has 2 (also Clobazam).
What mechanism field is on file for Phenobarbital and Cenobamate?
Cenobamate causes the levels of phenobarbital in your blood to go up. This makes it more likely that you will have a bad reaction to the phenobarbital.
Phenobarbital carries more major-labeled pairs than Cenobamate
SPL source-record counts only. This page's band is moderate · classes on file: Phenobarbital (Anticonvulsant (Barbiturate)); Cenobamate (Anticonvulsant).
Phenobarbital has 3 major-labeled pairs vs Cenobamate's 0. This page itself is in the moderate band, not the major band.
3 major · 13 moderate · 43 minor · 59 total
- Other moderate peers for Phenobarbital
- Canagliflozin
- Clarithromycin
- Dapsone Topical
- Dolutegravir/Lamivudine
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.