Cenobamate and Phenytoin interaction
Cenobamate and Phenytoin: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Cenobamate (Xcopri) label · effective 2025-08-25
Phenytoin: Gradually decrease phenytoin dosage by up to 50%.
…potential for reduced efficacy of these drugs, increase the dosage of lamotrigine or carbamazepine, as needed, when used concomitantly with XCOPRI. 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. phenobarbital…
Concomitant use with other CNS depressants or alcohol may have additive effects.
Anyone considering prescribing XCOPRI or any other AED must balance this risk with the risk of untreated illness.
Patients should be carefully observed for signs of central nervous system (CNS) depression, such as somnolence and sedation, when XCOPRI is used with other drugs with sedative properties because of potential additive effects.
From the Phenytoin label · effective 2024-12-24
Limited evidence suggests that HLA-B*1502 may be a risk factor for the development of SJS/TEN in patients of Asian ancestry taking other antiepileptic drugs associated with SJS/TEN, including phenytoin.
…defects), and abnormalities characteristic of fetal hydantoin syndrome, including dysmorphic skull and facial features, nail and digit hypoplasia, growth abnormalities (including microcephaly), and cognitive deficits, have been reported among children born to epileptic women who took phenytoin alone or in combination with other antiepileptic drugs during pregnancy.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.