Canadian patients who underwent low-risk surgery filled opioid prescriptions within a week of discharge at seven times the rate of Swedish patients, a new study reveals.

Nearly 79 per cent of Canadian patients collected opioids after their operation compared to just 11 per cent of Swedes, according to a report published in JAMA Network Open.

It claims to be the first study of its kind to assess the differences in opioid use after surgery for patients receiving similar procedures in different countries.

"Opioids are routinely prescribed for postoperative pain management in many countries, however the findings suggest the potential to reevaluate prescribing practices internationally," said Dr. Karim Ladha, co-author of the study and a clinician-scientist at the Li Ka Shing Knowledge Institute at St. Michael's Hospital in Toronto.

The study focused on adults in the U.S., Canada and Sweden who underwent gall bladder removal, appendix removal, meniscus repair in the knee and breast lump removal.

"The U.S. and Canada are similar in a lot of ways, both are the top consumers of opioids in the world," Dr. Ladha, who has worked in both countries, told in a phone interview.

The average amount of opioid dispensed for the initial prescription was lowest in Canada, followed by Sweden, with the highest in the U.S.

"We found that certain types of opioids, such as codeine and tramadol, were prescribed more often in Canada," said co-author Dr. Hannah Wunsch, a staff physician at the department of critical care medicine at Sunnybrook Health Sciences Centre.

"While prescribers may view these so-called weak opioids as safer alternatives, there is still the potential for misuse and life-threatening adverse effects."

The study examined the frequency, amount and type of opioids dispensed after surgery and points to differences in approaches to opioid prescribing, public attitudes regarding opioids for pain treatment and other factors related to drug marketing and regulation.

"Patients treated in the U.S. and Canada received opioids after surgery more often and in higher doses compared to patients treated in Sweden," the report concluded.

"Understanding the societal and cultural factors that influence these prescribing patterns could inform areas of further research and identify targets for future interventions."

Excessive postoperative opioid prescribing has been associated with increased risks of long-term opioid use and the development of opioid use disorder, the authors said.

"We probably give too many pills. There are a lot of studies that show a lot of the prescriptions given after surgery go unfilled," Dr. Ladha told

He added that those who do fill their prescriptions do not always complete the course, leaving left-over pills in the medicine cabinet, increasing the chances of them being misused.

Sixty to 90 per cent of people who misuse opioids get them from friends and family, Dr. Ladha said.

In 2018, nearly 4,500 opioid-related deaths occurred in Canada.

"We assume opioids to be the treatment of choice for acute pain," he said.

"But can we give someone Tylenol or ibuprofen and can that work. Patients in North America have this demand to be pain free.

"We may have got a little over zealous in our prescribing of opioids, we are doing things vastly different in this part of the world."

The data was analyzed last year at the not-for-profit research institute ICES, formerly the Institute for Clinical Evaluative Sciences, based at the Sunnybrook Health Sciences Centre in Toronto.

The final study sampled 84,653 patients in Canada.

Opioids tracked in the report include codeine, fentanyl, morphine, oxycodone and tramadol.

Codeine and tramadol accounted for around 58 per cent of postoperative prescriptions in Canada.

During the study time period, low-dose codeine was available over-the-counter in Canada and tramadol is still not considered a controlled or scheduled substance in Canada, although it became a controlled substance in 2007 in Sweden and in 2014 in the U.S.