Methadone substitution treatment vs opioid withdrawal to retain patients in treatment and reduce use — evidence summary

Summary of the evidence


Methadone substitution treatment was found in a systematic review (WHO, 2009, 3RCTs, N=505) to be more effective than opioid withdrawal followed by placebo in:

  • increasing retention in treatment (RR 3.05, 95 % CI 1.75 to 5.35);
  • reducing illicit opioid use (RR 0.32, 95 % CI 0.23 to 0.44).

Observational studies found the mortality rate in methadone treatment to be approximately one-third the rate out of treatment (RR 0.37, 95 % CI 0.29 to 0.48).

Methadone was found in one RCT (N=253) to reduce the risk of HIV infection by approximately 50 % (RR 0.45, 95 % CI 0.35 to 0.59) and a similar reduction in seroconversion rates was found in 3 observational studies (N=43 035) (RR 0.36, 95 % CI 0.19 to 0.66) when compared to withdrawal or no treatment.


Note: this evidence summary is only valid for the outcomes, target groups, settings and substances/patterns of use described below.

Name of response option:
Pharmacological treatment
Desired outcome(s):
reduce substance use
retain patients in treatment
Specific substance or pattern of use: