Six recent randomised control trials (RCTs) have suggested that supervised injectable heroin (SIH) can be effective in patients who persist in street heroin use during methadone treatment. However, short-term randomised control trials have limitations in assessing the effectiveness of treatments for addictive disorders, which are chronic and relapsing disorders of motivation. These RCTs particularly fail to capture the process of the SIH treatment and the diversity of influence and change over time.
This narrative review is based on the analysis of published data. Conclusions are drawn from a process of reflection informed by experience in delivering one of the published trials, subsequent experiences in varying the way SIH is delivered, and through consideration of possible mechanisms of action of SIH.
Many long-term, socially marginalised and demoralised people who are addicted to heroin experience few rewards from the stability afforded by methadone treatment. Supervised injected heroin is sufficiently reinforcing for many of these individuals to attend daily and participate in highly structured treatment. With an adequate daily dose of supervised methadone to avoid withdrawal dysphoria, occasional diamorphine injections—not necessarily twice daily, or even every day—is enough to hold people in treatment. Participation was associated with reduced amounts of non-prescribed drug use, a gradual change in self-image and attitude, and for some subjects, a movement towards social reintegration and eventual withdrawal from SIH.
Prescribed heroin is sufficiently motivating to hold a proportion of recidivist addicts in long-term treatment. Participation in structured treatment provides respite from compulsive drug use, and a proportion of subjects develop sufficient rewards from social reintegration to successfully withdraw from treatment. Such change, when it occurs, is slow and stuttering.