Oxcarbazepine and Phenobarbital Interaction
Drug interaction information between Oxcarbazepine and Phenobarbital.
Oxcarbazepine and Phenobarbital have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Oxcarbazepine and Phenobarbital. 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
Phenobarbital causes your body to process and remove the active part of oxcarbazepine more quickly than usual.
FDA Label Information
Reduced dose of phenytoin may be required ( 7.1 ) • Carbamazepine, Phenytoin, and Phenobarbital: Decreased plasma levels of MHD (the active metabolite). 7.2 Effect of Other Drugs on Oxcarbazepine Strong inducers of cytochrome P450 enzymes and/or inducers of UGT (e.g., rifampin, carbamazepine, phenytoin and phenobarbital) have been shown to decrease the plasma/serum levels of MHD, the active metabolite of oxcarbazepine (25% to 49%) [see Clinical Pharmacology ( 12.3 )].
Oxcarbazepine Also Interacts With
- Dolutegravir/Lamivudine moderate
- Tranylcypromine moderate
- Rifampin minor
- Phenytoin minor
- Bictegravir/Emtricitabine/Tenofovir minor
Phenobarbital Also Interacts With
- Nirmatrelvir/Ritonavir major
- Ranolazine major
- Voriconazole major
- Canagliflozin moderate
- Cenobamate moderate
Frequently Asked Questions
What SPL severity band is on file for Oxcarbazepine + Phenobarbital?
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?
Phenobarbital has 59 labeled pairs on file vs Oxcarbazepine's 18. In the minor band specifically: Oxcarbazepine has 16 (also Rifampin, Phenytoin, Bictegravir, Carbamazepine); Phenobarbital has 43 (also Estradiol, Doxycycline, Progesterone, Griseofulvin).
What mechanism field is on file for Oxcarbazepine and Phenobarbital?
Phenobarbital causes your body to process and remove the active part of oxcarbazepine more quickly than usual.
Phenobarbital carries more major-labeled pairs than Oxcarbazepine
SPL source-record counts only. This page's band is minor · classes on file: Oxcarbazepine (Anticonvulsant); Phenobarbital (Anticonvulsant (Barbiturate)).
Phenobarbital has 3 major-labeled pairs vs Oxcarbazepine's 0. This page itself is in the minor band, not the major band.
0 major · 2 moderate · 16 minor · 18 total
- Other minor peers for Oxcarbazepine
- Rifampin
- Phenytoin
- Bictegravir
- Carbamazepine
3 major · 13 moderate · 43 minor · 59 total
- Other minor peers for Phenobarbital
- Estradiol
- Doxycycline
- Progesterone
- Griseofulvin
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.