Randomized trial of supervised injectable versus oral methadone maintenance: report of feasibility and 6-month outcome.

AIM

To assess the feasibility of a randomized clinical trial of supervised injectable versus oral methadone maintenance and to assess medium-term treatment outcomes.

DESIGN

Randomized clinical trial of supervised injectable versus supervised oral methadone maintenance treatment (MMT). Trial participants were dependent illicit opiate injectors allocated at intake to supervised injectable or oral methadone maintenance treatment.

SETTING

Specialist addictions treatment centre in South London.

SUBJECTS

Forty dependent illicit opiate injectors seeking methadone maintenance treatment.

INTERVENTIONS

Daily supervised injectable and oral methadone maintenance, delivered at the treatment centre.

MAIN OUTCOME MEASURES

Frequency of illicit heroin use and frequency of illicit drug injecting during 30 days before intake to treatment and prior to 6-month follow-up.

SECONDARY OUTCOME MEASURES

frequency of use of illicit methadone, crack cocaine, benzodiazepines and alcohol, physical and psychological health symptoms and acquisitive crime.

RESULTS

Injectable and oral MMT were both generally acceptable to the study participants: there was a high level of agreement to enter the randomized trial, and subsequent retention in treatment was good. The average number of days of illicit heroin use reduced from 22.2 to 7.6 for the injectable MMT group and from 22.4 to 8.7 for the oral MMT group. The average number of days of illicit injecting reduced from 25.7 to 10.8 days for the injectable group and from 20.1 to 11.9 days for the oral group. Patients' physical and psychological health symptoms and involvement in acquisitive crime also reduced in both groups. Treatment satisfaction ratings at follow-up were higher among patients in the injectable MMT group. The ratio for the actual medication costs between injectable and oral MMT was 6.8:1, and for the direct operational costs was 4.7:1. There was some evidence of a differential patient response with greater reductions in heroin use occurring among patients who were daily illicit injectors and had poorer psychological and physical health (at entry) who were allocated to injectable MMT.

CONCLUSIONS

Conduct of the trial has demonstrated that it is feasible to implement supervised injectable methadone maintenance treatment in the context of (although separate from) a specialist oral methadone maintenance service. Patients assigned to receive either supervised injectable or oral MMT had broadly equivalent, positive during-treatment outcomes at 6-month follow-up. Future studies should seek to identify patient characteristics which are linked to good outcome in injectable MMT. Practical evidence-based guidance to physicians about determining which patients are more suitable for injectable MMT is urgently needed.