 3. Patient is receiving drugs that interacting with methadone, such as delavirdine, fluconazole, fluvoxamine, bravavir, amprenavir, efavirenz, lopinavir, nelfinavir, nevirapine, carbamazepine, dexamethasone Patients receiving short term chemotherapy-related doses are permitted , phenytoin, rifampin, or grapefruit,. 