Prescribing heroin instead of methadone is more effective and less costly in treating street drug addiction relapses, a new analysis suggests.

It was a collaboration with UBC, the University of Montreal and the Northern Ontario School of Medicine.

"We gave them option of trying methadone or diacetylmorphine [heroin] under medically supervised conditions, and we found people who were getting diacetylmorphine were retained in treatment much, much longer, so they had a much better outcome," said study head Dr. Aslam Anis, director of the Centre for Health Evaluation and Outcome Sciences at St. Paul’s Hospital in Vancouver.

Most of the savings in the mathematical model were attributed to how those prescribed heroin stayed in treatment longer and spent less time in relapse than those randomly assigned to receive methadone.

By staying in treatment, health-care costs were lower when the cost of the drugs, counselling and social supports were added up.

"Our model indicated that diacetylmorphine would decrease societal costs, largely by reducing costs associated with crime, and would increase both the duration and quality of life of treatment recipients," the study's authors concluded.

While the clinical trial was based on a year’s worth of data, the researchers considered different timeframes — such as one year, five years and over a lifetime— in their analysis.

They estimated the societal cost of $1.14 million over the lifetime of a person receiving methadone, compared with $1.10 million for someone on diacetylmorphine injections.

Methadone is taken orally, usually mixed with juice. It works by blocking opioid receptors in the brain to take away cravings and prevent withdrawal symptoms.

In 2009, the researchers reported in the New England Journal of Medicine that diacetylmorphine is more cost-effective than methadone among the same group of addicts in Vancouver and Montreal, in terms of staying in treatment or quitting heroin altogether and reducing use of illegal drugs.

The cost-effectiveness study, published in Monday's issue of the Canadian Medical Association Journal, focused on more than 250 people addicted to opioid drugs who had tried methadone replacement therapy at least twice and were unable to stay drug-free.

Dutch studies came to similar conclusions for people in methadone maintenance programs. The North American trial, called NAOMI, looked at those who have been out of treatment for at least six months.

In the latest Canadian study, drawbacks include a lack of data on opioid users reaching a state of abstinence and on the long-term patterns, the authors acknowledged.

The findings do not apply to people who haven't tried methadone replacement therapy.

Dr. Meldon Kahan, who treats opioid dependency as part of his Toronto practice, suggested addicts who received methadone in the trial were given sub-optimal doses of the drug, leading to a higher drop-out rate than among those prescribed heroin.

The researchers also developed a web-based tool for policymakers to calculate the estimated costs and savings of using this approach depending on the age and sex of addicts in their population.