a syringe imageApril 23 2018

Buprenorphine has been found to have lower rates of overdose death than methadone when used in opioid substitute therapy. The impact was particularly seen in the first four weeks of treatment, researchers from the University of Bristol have found.

Data from 11,000 GP practices indicated that buprenorphine was prescribed for approximately a third of opioid substitution patients, while methadone was used in two-thirds of cases.

“Patients on buprenorphine had substantially lower rates of overdose death during treatment compared to those on methadone: four times lower in the first 4 weeks (0.3% compared with 1.24%) and almost twice as low during the rest of time on treatment (0.18% compared with 0.33%). These differences remained even after adjusting for differences in patient and practice characteristics for those prescribed methadone or buprenorphine,” said the National Institute for Health Research.

“Patients on buprenorphine also had lower rates of all-cause mortality during and immediately after treatment – which may be because patients who are older and have other physical and mental health complications may do better on buprenorphine than methadone.”

Although numbers of patients in opioid substitution therapy are at record levels, the number of drug-related deaths is continuing to rise.

Professor Matthew Hickman, from the NIHR Health Protection Research Unit and Population Health Sciences at University of Bristol, was one of the lead authors of the study published in Addiction. “Our research provides evidence to support a change in the way treatment is delivered that could save lives,” he said. 

“We now need trials in the UK on how we combine different opioid substitution treatments alongside other behaviour change interventions to retain people in treatment long enough to reduce the number of drug related deaths in the population.”

NIHR announcement    
M Hickman et al. ‘The impact of buprenorphine and methadone on mortality: a primary care cohort study in the United Kingdom’. Addiction. Published online April 19 2018.