Aims: To assess the efficacy of buprenorphine compared with methadone maintenance therapy for opioid dependence in a large sample using a flexible dosing regime and the marketed buprenorphine tablet.
Design: Patients were randomized to receive buprenorphine or methadone over a 13-week treatment period in a double-blind, double-dummy trial.
Setting: Three methadone clinics in Australia.
Participants: Four hundred and five opioid-dependent patients seeking treatment.
Intervention: Patients received buprenorphine or methadone as indicated clinically using a flexible dosage regime. During weeks 1-6, patients were dosed daily. From weeks 7-13, buprenorphine patients received double their week 6 dose on alternate days.
Measurements: Retention in treatment, and illicit opioid use as determined by urinalysis. Self-reported drug use, psychological functioning, HIV-risk behaviour, general health and subjective ratings were secondary outcomes.
Findings: Intention-to-treat analyses revealed no significant difference in completion rates at 13 weeks. Methadone was superior to buprenorphine in time to termination over the 13-week period (Wald chi 2 = 4.371, df = 1, P = 0.037), but not separately for the single-day or alternate-day dosing phases. There were no significant between-group differences in morphine-positive urines, or in self-reported heroin or other illicit drug use. The majority (85%) of the buprenorphine patients transferred to alternate-day dosing were maintained in alternate-day dosing.
Conclusions: Buprenorphine did not differ from methadone in its ability to suppress heroin use, but retained approximately 10% fewer patients. This poorer retention was due possibly to too-slow induction onto buprenorphine. For the majority of patients, buprenorphine can be administered on alternate days.