Carbamazepine and Felbamate interaction
Carbamazepine and Felbamate: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Felbamate (Felbatol) label · effective 2025-08-15
IT IS NOT KNOWN WHETHER CONCOMITANT USE OF OTHER ANTIEPILEPTIC DRUGS AND/OR OTHER DRUGS AFFECT THE INCIDENCE OF HEPATIC FAILURE.
Carbamazepine Felbatol ® causes a decrease in the steady-state carbamazepine plasma concentrations and an increase in the steady-state carbamazepine epoxide plasma concentration.
The carbamazepine steady-state C min decreased 31% to 5±1 micrograms/mL when felbamate (3000 mg/day, divided into three doses) was coadministered.
Carbamazepine epoxide steady-state C min concentrations increased 57% from 1.0±0.3 to 1.6±0.4 micrograms/mL with the addition of felbamate.
Carbamazepine Carbamazepine causes an approximate 50% increase in the clearance of Felbatol ® at steady-state and, therefore, the addition of carbamazepine results in an approximate 40% decrease in the steady-state trough concentrations of Felbatol ® as compared to the same dose of Felbatol ® given as monotherapy.
From the Carbamazepine (EQUETRO) label · effective 2025-08-19
Limited evidence suggests that HLA-B*1502 may be a risk factor for the development of SJS/TEN in patients of Chinese ancestry taking other anti-epileptic drugs associated with SJS/TEN, including phenytoin.
Such drugs include the following: Aminophylline, c isplatin, doxorubicin, felbamate, phosphenytoin, methsuximide , phenobarbital, phenytoin, primidone, rifampin and theophylline.
…clonazepam, clozapine, cyclosporin, delavirdine, desipramine, diazepam, dicumarol, dihydropyridine calcium channel blockers (e.g., felodipine), doxycycline, ethosuximide, everolimus, felbamate, glucocorticoids, haloperidol, imatinib, itraconazole, lamotrigine, levothyroxine, lorazepam, methadone, methsuxamide, mianserin, midazolam, mirtazapine, nefazodone, olanzapine,…
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.