 - h. Enzyme inducing anticonvulsants : Patients may not be taking enzyme - inducing anticonvulsants, and may not have received these medications within 1 week of entry, as these patients may experience different drug disposition. These medications include: Carbamazepine Tegretol, Felbamate Felbtol, Phenobarbitol, Phenytoin Dilantin, Primidone Mysoline, Oxcarbazepine Trileptal, and, Herbal preparations: St. Johns wort Hypericum perforatum, hypericine. 