Painkiller prescribing varies dramatically among family physicians: study

Some physicians are prescribing opioids such as OxyContin 55 times as often as others, according to a new study led by St. Michael's Hospital and the Institute for Clinical Evaluative Sciences (ICES). The study found most opioid-related deaths occur among patients treated by physicians who frequently prescribe opioids, suggesting doctors who prescribe a lot of opioids may not be doing so safely.

"We found that the 20 per cent of family doctors who are frequent prescribers wrote 55 times as many prescriptions as the 20 per cent of family doctors who prescribe opioids the least. This large variation in practice is concerning," says Dr. Irfan Dhalla, a general internist at St. Michael's Hospital and an adjunct scientist at ICES.

The study, published in the March edition of the journal Canadian Family Physician, examined opioid prescribing rates among family physicians in Ontario. Researchers found doctors who frequently prescribe opioids are also more likely to write the patient's final prescription before death.

"Family physicians are caught in the middle. On the one hand, there are many patients suffering terribly from chronic pain who can't get relief from other treatments. On the other hand, the evidence for long-term treatment with opioids is very weak," says St. Michael's family physician Dr. Philip Berger. "If the drugs were safe, it wouldn't be an issue. But unfortunately they do carry significant risks -- most notably addiction and death from overdose. And it is important to recognize that one reason opioids are prescribed so often is that the pharmaceutical industry has marketed these drugs very aggressively."

Deaths related to opioids in Ontario have more than doubled -- from 13.7 deaths per million residents in 1991 to 33.3 deaths per million residents in 2006. Of the 423 deaths that occurred in 2006, oxycodone -- the active ingredient in OxyContin -- was the opioid most frequently associated with an overdose death.

In 2010, the provincial government passed the Narcotics Safety and Awareness Act, which will enable the Ministry of Health and Long-Term Care to better track opioid prescribing in Ontario.