Felbamate and Phenobarbital interaction
Felbamate and Phenobarbital: the Felbamate prescribing label 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.
Phenobarbital Coadministration of felbamate with phenobarbital causes an increase in phenobarbital plasma concentrations.
Phenobarbital It appears that phenobarbital may reduce plasma felbamate concentrations.
Use in Conjunction with Other Antiepileptic Drugs (see DOSAGE AND ADMINISTRATION ) The addition of Felbatol ® to antiepileptic drugs (AEDs) affects the steady-state plasma concentrations of AEDs.
CBZ epoxide ↓ ↑ ↓ Phenobarbital ↑ ↓ Specific Effects of Felbatol® on Other Antiepileptic Drugs Phenytoin Felbatol ® causes an increase in steady-state phenytoin plasma concentrations.
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.