TORONTO - Accidental deaths due to use of opioid painkillers in Ontario have soared over the past couple of decades, increasing dramatically after a new long-acting version of the drug oxycodone - sold as OxyContin - hit the market, a new study suggests.
Opioid-related deaths claim more people in Ontario than HIV, with 27 in a million people dying from an opioid-induced overdose in 2004 versus 12 in a million from HIV, the researchers reported Monday in the Canadian Medical Association Journal.
Lead author Dr. Irfan Dhalla said there's been a suspicion among physicians that deaths due to prescription opioid use were on the rise, but this was the first effort to quantify it in Ontario. He admitted the effect was greater than he anticipated.
"When you think about the fact that there are far more people dying from prescription opioids than from HIV, that to me is surprising," said Dhalla, who practises general internal medicine at St. Michael's Hospital in Toronto.
He and others said similar problems, though in some cases caused by other prescription opioids, are probably being experienced in other parts of the country.
The magnitude of the problem is probably worse than the study implies, Dhalla and other addictions researchers said. The way the data were collected, it is unlikely opioid-induced deaths in seniors would have been captured, Dhalla said, adding that despite that, these types of deaths are likely happening in that age group.
And a leading addictions researcher said the situation has worsened since 2004, the end of the period studied by Dhalla and his colleagues.
"We have strong reason to assume that these numbers kept going up in the last five years because our overall consumption of opioids kept increasing in those years," said Benedikt Fischer, interim director at the Centre for Applied Research in Mental Health and Addictions at Simon Fraser University, in Burnaby, B.C.
"We know that. And given that there's a likely association between those things, these deaths are likely higher today than they were in 2004."
Fischer said the work puts on the radar a problem that has gone undetected in Canada until now.
"This has been a sleeper problem for a long time," said Fischer, who wrote a commentary published with the study in the journal.
"We dish these drugs out like there's no tomorrow here in this country."
In fact, Fischer and his commentary co-author, Jurgen Rehm of Toronto's Centre for Addiction and Mental Health (CAMH), noted that on a per capita basis, Canadians take five times more prescription opioids than do residents of the United Kingdom.
Opioids are strong analgesics - a.k.a. painkillers - which bind to receptors in the central nervous system, decreasing perception of pain and increasing pain tolerance. Members of this class of drugs include morphine, heroin, codeine, oxycodone and its slow-release cousin, OxyContin.
The latter, dubbed "hillbilly heroin," has been the source of significant controversy. While its manufacturer, Purdue Pharma, insisted the slow-release feature of the drug would lower the risk of users becoming addicted, users themselves quickly learned they could speed up the kick the pills deliver by simply grinding up or chewing the pill.
"OxyContin is not just another Tylenol No. 3," said Dhalla. "It has higher risks. It's a much, much stronger opioid."
Dhalla and his colleagues examined trends in the prescribing of opioids in Ontario from 1991 to 2007 and went over coroners' reports of deaths in which opioid use was listed for the period between 1991 and 2004.
Over the period, all opioid-related deaths doubled, to 27.2 per million in 2004 from 13.7 per million in 1991. But after OxyContin was added to Ontario's provincial formulary in 2000, deaths involving oxycodone increased fivefold. (In post-mortem toxicology testing, it's not possible to distinguish OxyContin from oxycodone.)
Opioids were implicated in 3,406 deaths. Most appeared to be inadvertent; coroners ruled the deaths were unintentional in 52.4 per cent of the cases. Suicide was listed on only 23.6 per cent of death records.
The vast majority of the people who died had also consumed other substances that depress the nervous system, such as alcohol or sleeping pills.
"It's this combination of a lot of different drugs which is actually leading to the death," said Rehm, a senior scientist at CAMH.
"And we do not know causally (if) it's substance A or B. It's the combination of all of them. And in this combination, unfortunately, oxycodone is having a major effect."
Dhalla said opioids on their own can slow breathing to the point where a person slips into a coma; when combined with alcohol or sleeping pills, that risk is even greater.
"I think the saddest cases are probably where somebody has gotten into a friend's OxyContin or relative's OxyContin and just taken what appears to have been a very small amount just for kicks and then not woken up," he said.
"And we did see some of those cases."
Addressing the problem won't be easy, the experts suggested. That's because the increased use sprang from a push to better control severe and chronic pain - a problem which many clinicians felt was too long ignored.
But the solution to that problem appears to have resulted in what Fischer and Rehm called a "prescription-opioid-rich environment" - opioids in far too many medicine cabinets.
"The question is how to separate the good from the bad and how to go about that," Fischer said.
"This is a very complex problem. And we can't just now pull out the hammer and start hammering at this. Because we'll probably do a lot more collateral damage than we're doing good."
