VANCOUVER — Researchers in British Columbia have published a study that suggests prescription opioids prevent overdose deaths among people with an addiction to potentially toxic street drugs.
They found that those who were prescribed at least one day's supply of opioids were 55 per cent less likely to die from overdose in the following week when compared with a similar group without a prescription. Those who had a four-day or longer prescription cut their risk of death by 89 per cent.
The study focuses on prescribing guidance that British Columbia introduced in March 2020 for people who could fatally overdose during the pandemic as they sought a diminishing supply of illicit substances and risked COVID-19 transmission.
British Columbia is Canada's only jurisdiction to launch such a policy amid an ongoing public health emergency that has claimed more than 13,000 lives in the province since 2016 due to overdoses fuelled by drugs contaminated with fentanyl.
The study, published Wednesday in the British Medical Journal, uses anonymized data on hospital visits, overdoses and deaths among 5,882 people with an opioid or stimulant use disorder who were prescribed medications between March 2020 and August 2021.
About 91 per cent of the total number of people were prescribed opioids such as hydromorphone or morphine and the remaining received stimulants including methylphenidate. Just over 500 of them had prescriptions for both opioid and stimulant disorders.
Lead author Amanda Slaunwhite, senior scientist with the BC Centre for Disease Control, said people who were prescribed opioids as part of the Risk Mitigation Guidance program had a 61 per cent lower risk of dying from any cause a week later and that rose to 91 per cent with a four-day prescription or longer prescription over the same period.
She said researchers focused on a one-week period based on their hypothesis that safer medications would not be prescribed long term.
"Most people didn't receive a continuous prescription, it was episodic," she said. "It's like birth control is only effective so long as you're taking it. And these medications are only effective in that immediate period when people are prescribed them. If people returned to the illicit drug supply then their risk of overdose would dramatically increase."
Findings regarding people who were prescribed stimulants were not statistically significant due to the small sample size and researchers could not confirm if either those who received opioids or stimulants actually took them.
People who use or previously used illicit drugs provided guidance in interpreting the results and formulating questions related to the provincial health data, said Slaunwhite, also an assistant professor at the University of British Columbia's school of population and public health.
She said researchers will now focus on looking at the unintended consequences of safer supply, including people giving away or selling their medications and the possible impact of substance use among youth.
Dr. Paxton Bach, an addictions medicine physician and a co-author on the study, said less than five per cent of people with an opioid use disorder in British Columbia are accessing medications, and one reason may be that some physicians are reluctant to prescribe it.
"I hope that some people who have been awaiting this type of evaluation take these results into account when they're deciding how they want to proceed in their respective practices," said Paxton, adding the research may guide other provinces in their own safer-supply programs.
"I would not ask anyone to necessarily adopt our approach directly but I hope that our experience and these results are taken into consideration and used to inform thoughtful policy approaches to the overdose crisis that can be implemented and tailored to every individual province and context."
The study included the First Nations Health Authority, the BC Centre on Substance Use and the University of Victoria's Canadian Institute for Substance Use Research.
Previous studies on prescribing alternative medications to protect people from the illegal drug supply is limited and did not include provincewide health data or a control group.
An estimated 100,000 people in British Columbia are believed to have an opioid use disorder and an average of seven people a day die from overdose. The coroners service has said the province is expected to have had a record number of fatalities from illicit substances when it finalizes the latest data for 2023.
This report by The Canadian Press was first published Jan. 11, 2024.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
Camille Bains, The Canadian Press
