- Enzyme-inducing anticonvulsants or other medications: Patients who are currently receiving the enzyme inducing anticonvulsants: phenytoin, phenobarbital, carbamazepine, oxcarbazepine are not eligible. Patients who are currently taking rifampin, voriconazole, itraconazole, ketoconazole, aprepitant, or St. John's Wort are not eligible