A new meta-study has found that staying in methadone and buprenorphine treatment protects against all cause and overdose mortality.
The study, published in the British Medical Journal (BMJ), states that opioid substitution treatment, either with methadone or buprenorphine, has been shown to be safe and effective in suppressing illicit opioid use, improving physical and mental wellbeing, and reducing mortality.
Growing evidence, however, suggested that mortality experience during and after opioid substitution treatment is time varying and differs with either treatment type of drug.
The study carried out a systematic review of cohort studies which provided valuable evidence on the mortality experience of opioid dependent people at different periods of methadone and buprenorphine substitution treatment.
The BMJ study found that in patients using methadone maintenance treatment there are, fewer deaths than in patients who discontinue it. Mortality risk among opioid users during treatment is less than a third of that expected in the absence of opioid substitution treatment.
Buprenorphine maintenance treatment is probably also effective in reducing mortality in opioid users, but quantification of deaths that were averted requires further studies.
There were 706 drug-related deaths in Scotland in 2015, with heroin and/or morphine implicated in, or potentially contributed to, the cause of 345 deaths (49 per cent of the total) – more than in any previous year. Opiate-replacement therapy is a protective factor against overdose deaths.
The mortality risk in the induction phase of methadone (first four weeks) is high but seems to decreases substantially during this period, with further stabilisation in the remaining time in treatment. This did not occur with buprenorphine. The mortality risk in the four weeks immediately after cessation of either treatment is high.
The study concludes that overdoses are preventable causes of death warranting wide implementation of preventive interventions. The review has provided evidence that methadone and probably buprenorphine reduce mortality among people dependent on opioids.
Policymakers, clinicians, and those responsible for drug treatment systems should work to ensure the availability of such treatment, remove access barriers, and promote engagement.
Precautions should be taken during and after opioid substitution treatment to increase safety.
Firstly, careful clinical assessment of opioid tolerance before onset of treatment to establish a safe induction dose seems warranted.
Secondly, monitoring during the induction period is important, especially for methadone, with clinicians considering adjusting opioid doses, monitoring mental and somatic problems, and preventing the use of opioids obtained on the illicit drug market.
In addition, education of patients about the risk of overdose risk and use of “take home” naloxone is warranted.