Here’s a simple, if arresting, fact: The United States and Canada have the highest rates of prescription opioid use in the world. After a close examination of the numbers on the northern side of the border, researchers at St. Michael's Hospital and the Institute for Clinical Evaluative Sciences discovered differing patterns of opioid use across the provinces, while overall in Canada, high-dose opioid prescriptions increased by 23 percent between 2006 and 2011. What were the most popular drugs? Oxycodone and morphine say the scientists behind this new study.

It's A North American Thing

In the U.S. during 2012, doctors wrote enough scripts for painkillers so that every single adult could have a bottle all to themselves: 259 million prescriptions in total. While many people are suffering chronic pain, this does not erase the sad fact that 46 people die each day from an overdose of painkillers. Additionally, 10 of the highest prescribing states are located in the South, generally one of the poorest areas of the nation.

A similar pattern of incongruity was found north of the border. In the current study, the prevalence of high-dose prescribing, though widespread across Canada, differed considerably between provinces. Ontario and Quebec exhibited the highest and lowest rates of high-dose opioid dispensing, respectively. Ontario dispensed more than one unit per person — 1,382 high-dose opioid units per 1,000 people. Quebec, on the other hand, dispensed only 368 high-dose opioid units per 1,000 people. "Provinces not only differed in their prevalence of high-dose opioid prescribing, but each province also appears to favor different opioids," said Dr. Tara Gomes, a scientist at the Li Ka Shing Knowledge Institute of St. Michael's Hospital and lead author.

Oxycodone is the drug most commonly prescribed in Alberta and Ontario, for instance, while morphine is popular in British Columbia. The rates of increase across the six-year study period also varied considerably from province to province. High-dose opioid dispensing rates remained relatively stable in Alberta and British Columbia, increasing by 6.3 percent and 8.4 percent, respectively. Newfoundland and Labrador showed an astounding 84.7 percent spike, while in Saskatchewan, prescription rates rose by 54 percent.

In total, more than 180 million units of high-dose tablets and patches were dispensed across Canada during the six-year study period. Nearly half were oxycodone tablets, while morphine tablets comprised nearly a quarter. Hydromorphone tablets and fentanyl patches were also commonly prescribed, at 18 percent and nine percent, respectively. The overall rates of high-dose opioid dispensing increased from 781 units per 1,000 people to 961 units per 1,000 people during the study period.

While the per capita rate of high dose opioid prescriptions increased steadily for years, the numbers plateaued in 2009 and 2010. Possible reasons? According to the researchers, the plateau coincides with the release of Canadian medical guidelines for opioid use, plus a scholarly article highlighting the dramatic increase in fatal overdoses. Prior to the introduction of guidelines, clinical practice guidelines provided no recommended maximum dose and many experts went so far to suggest doses could be increased with little risk of harm. While a drug problem exists, the researchers remain hopeful. “These findings suggest that although a national strategy is likely necessary, different provinces may need slightly different approaches," Gomes said.

Source: Gomes T, et al. Canadian Family Physician. 2014.