• A randomized clinical trial compared four methods of outpatient withdrawal from heroin. Sixty-one subjects were assigned in a double-blind manner to treatment with either methadone or methadyl acetate. Within each drug group, subjects were assigned to detoxification programs either within the standard three-week period or in an extended six weeks of treatment. Outcome measures included retention to the end of the dosing schedule, use of illicit drugs during treatment, subjective discomfort, satisfaction, staff ratings of global progress, and durability of change at a three-month follow-up. Methadyl acetate performed similarly to methadone in most respects. Six-week withdrawal showed some temporary benefits over standard treatment, but these advantages should be weighed against the greater cost of the longer treatment and similarity of follow-up outcome.