When it comes to treatment for opioid addiction, figuring out which medication works best for each individual addict is key. A recent study conducted by researchers from the University of Bristol, King’s College London and the National Drug and Alcohol Research Centre at UNSW in Australia has revealed that people who are dependent on opioids are five times more likely to die within the first four weeks of treatment with methadone.

“Clinicians providing opioid substitution treatment face an important dilemma: Which is more likely to reduce patient risk, buprenorphine or methadone?” said Dr. Jo Kimber, lead author and a researcher at the National Drug and Alcohol Research Centre UNSW and King’s College London, in a statement. “Buprenorphine is argued to have a superior safety profile to methadone but a higher drop-out rate. Our data suggests at least at the beginning of treatment for heroin use that buprenorphine has clear benefits over methadone in reducing mortality risk.”

Kimber and her colleagues analyzed the medical records of 32,033 patients who were being treated for opioid dependence between 2001 and 2010 with either methadone or buprenorphine. There are currently 50,000 Australians and over 100,000 people in the UK who are currently being treated for heroin or opioid addiction with a pharmacotherapy treatment.

Patients from the study prescribed methadone were five times more likely to die from any cause in their first four weeks of treatment compared to those who were prescribed buprenorphine. That risk for death went back down after the initial four weeks of treatment.

“The findings support a stepped approach to treatment,” explained Professor Louisa Degenhardt from the National Drug and Alcohol Research Centre. “Opioid substitution therapy is proven to be a cost effective and safe treatment for opioid dependence. It not only reduces risk of death but also involvement in crime and imprisonment.”

Although buprenorphine is largely considered the safer of both treatments due to the effect methadone has on the user’s respiratory system, it also leads to more relapses. The Australian Institute of Health and Welfare estimates that around two-thirds of people dependent on opioids are being treated with methadone, while the remaining third is prescribed buprenorphine.

“These findings are of importance to GPs treating patients with drug-dependency problems. One way to reduce risks might be to commence treatment on buprenorphine for the first four weeks and then switch to methadone at a later stage without increased risk,” said Professor Matthew Hickman, professor in public health and epidemiology at the University of Bristol.

According to the Centers for Disease Control and Prevention, around 5,000 people each year die as a result of overdoses tied to methadone use. In spite of the Food and Drug Administration’s warnings regarding methadone use in 2006, over four million methadone prescriptions were written in 2009 for pain.

Source: Degenhardt L, Randall D, Hickman M, Larney S, Kimber J. Mortality risk of opioid substitution therapy with methadone versus buprenorphine: a retrospective cohort study. Lancet Psychiatry. 2015.