Dose-response effects of methadone in the treatment of opioid dependence.

OBJECTIVE: To compare the dose effectiveness of low to moderate doses of methadone in a sample of a contemporary population of opioid abusers, because the optimal dosing of methadone in the treatment of opioid dependence remains an issue.

DESIGN: A randomized, double-blind, placebo-controlled study.

SETTING: A methadone treatment research clinic.

PATIENTS: Participants (n = 247) were opioid-dependent patients with a high rate of cocaine use.

INTERVENTION: All participants were initially treated with active methadone for a minimum of 5 weeks and then received 15 weeks of stable dosing at 50, 20, or 0 mg per day. Individual counseling and group therapy were included.

MEASUREMENTS: Treatment retention and illicit drug use as determined by intensive urine monitoring.

RESULTS: Retention was better for patients who remained on active medication. By treatment week 20, retention was 52.4% for the 50-mg, 41.5% for the 20-mg, and 21.0% for the 0-mg group (50 versus 0 and 20 versus 0, P < 0.05; 50 versus 20, P > 0.05). Only the 50-mg treatment group had a reduced rate of opioid-positive urine samples (56.4% versus 67.6% and 73.6% for the 20-mg and 0-mg groups, respectively; P < 0.05) and cocaine-positive urine samples (52.6% versus 62.4% and 67.1% for the 20- and 0-mg groups, respectively; P < 0.05).

CONCLUSIONS: There is a dose-response effect for methadone treatment. Doses as low as 20 mg may improve retention but are inadequate for suppressing illicit drug use.