During the first week of induction onto methadone, participants will be administered fixed increasing doses of methadone starting at 30 mg daily and increased to 60 mg daily by the end of the first week. This methadone dose will be adjusted for stabilization of opiate withdrawal symptoms using a flexible dosing from 40 mg up to 150 mg. This range has been found to be adequate for the vast majority of patients receiving methadone in our program and is designed to accommodate participants who may not be able to tolerate the higher maintenance doses or may still experience withdrawal symptoms, respectively. We may increase or decrease this amount on a case-by-case basis based on physician assessment of self-reported and observed symptoms.