Date: Mon. Dec. 7 2009 1:20 PM ET

Deaths in Ontario from prescription narcotics have doubled in the last five years, fuelled in part by the addition of OxyContin to the province’s public drug program, a new study suggests.

The study, led by doctors at St. Michael’s Hospital and the Institute for Clinical Evaluative Sciences (ICES) in Toronto, found that deaths from opioid pain relievers soared from 13.7 deaths per million residents in 1991 to 27.2 deaths per million residents in 2004.

And the addition of a long-acting form of oxycodone, called OxyContin, to the province’s drug formulary in January 2000 corresponded with a five-fold increase in oxycodone-related deaths. The drug formulary funds medications for seniors, welfare recipients and people with disabilities.

“We were quite surprised by the number of deaths that related to prescription opioids. Towards the end of our study, there were well in excess of 300 deaths each year in Ontario alone,” lead author Dr. Irfan Dhalla told CTV News.

The researchers hope the figures will be eye-opening to both patients and doctors, who may not realize just how dangerous these drugs can be.

Dhalla, a doctor and researcher at St. Michael’s, says his team conducted the study after noting anecdotally a rise in patients dying from narcotic pain killers, which are among the most commonly prescribed drugs in Canada.

The medications are used to treat people with moderate-to-severe pain but can have fatal side effects, because they can lead to depressed breathing and decreasing level of consciousness.

To determine the scope of the problem, the researchers reviewed nearly 7,100 files at the Office of the Chief Coroner for Ontario. They then linked these files with provincial data on physician visits and medication prescribing.

They also analyzed data from IMS Health Canada, an organization that tracks the sales of prescription drugs, to see how the numbers of prescriptions have been rising in recent years.

They found prescriptions for oxycodone in Ontario rose by more than 850 per cent during the study period — an increase that was much larger than for any other narcotic pain reliever.

They also noted that after OxyContin was added to the provincial drug plan in 2000, deaths from any opioid increased by 41 per cent over the next five years. In fact, deaths from prescription opioids in Ontario far outnumbered those from heroin.

More potent than morphine

Most of the deaths were accidental, though 23.6 per cent were deemed suicides, while in another 22 per cent, the manner of death was undetermined.

“I think the magnitude of this increase was really surprising to us,” said study co-author Dr. David Juurlink, a senior ICES researcher and a staff physician at Sunnybrook Health Sciences Centre.

The study appears in this week’s issue of the Canadian Medical Association Journal.

Dhalla notes that many of the narcotic deaths happened to people who had received a prescription for the drug in the month before they died, suggesting that most were using the medication not for recreational use but for legitimate pain relief.

“So most of the deaths we observed were accidental,” he said. “Our sense is that most physicians may not appreciate quite how dangerous these drugs are.”

He says there appears to be a perception in the medical community that oxycodone is simply a different form of Tylenol 3, whose active ingredient is codeine. In fact, oxycodone is even more potent milligram by milligram than morphine.

“It’s a dangerous drug. In the wrong patient or in combination with sleeping drugs or alcohol, this drug can kill people,” he says.

Many patients, too, don’t fully appreciate the potential danger of opioids, “particularly when they are taken in combination with other sedating drugs or alcohol,” Juurlink suspects.

He notes that the manufacturer of OxyContin, Purdue Pharma, promoted it heavily when it was first introduced and that may be why the drug became so popular among physicians.

Two years ago, Purdue and three of its former executives, pleaded guilty to misleading the public about OxyContin’s risk of addiction and less subject to abuse than other pain medications. In fact it is highly addictive and can be used by recreational drug users, who have dubbed it “hillbilly heroin.”

People who abuse the medication crush the pills and then snort or inject the drug so that its pain-killing properties — meant to be spread out over 12 hours — are absorbed all at once.

Last month, Ontario promised new rules to restrict how OxyContin is prescribed. The Health Ministry is considering imposing guidelines to cap the amount of pills that can be dispensed at one time.

The new measures would also include a computer tracking system that would monitor how much of the drug is going out by transmitting every prescription into a provincial database, which will send out an alert if someone tries to fill a prescription for the same drug two days in a row.

Story and video copyright CTV News