Opioid deaths twice as likely among male patients: study

More than one in 10 people prescribed an opioid painkiller for the first time become chronic users, say Ontario researchers who also found the men are twice as likely as women to die from causes related to the drugs.

The study in Thursday's issue of the journal PLOS One, published by the Public Library of Science, was based on the records of more than 250,000 people in Ontario aged 15 to 64 who started receiving the powerful painkillers between 1997 and 2010.

The opioids, such as oxycodone, fentanyl, codeine and hydrocodone, were originally prescribed for severe, chronic noncancer pain but their use has skyrocketed in North America.  The drugs are prescribed short-term for acute pain after an injury as well as for chronic conditions such as low back pain, osteoarthritis and fibromyalgia.

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"Men were more likely than women to escalate to high-dose opioid therapy and more than twice as likely to die of an opioid overdose," the study's senior author, Dr. David Juurlink, head of clinical pharmacology and toxicology at the University of Toronto and his team said.

"Although our findings underscore the importance of judicious opioid use in both men and women, they suggest that particular vigilance be applied to men, especially as doses begin to escalate."

'Surprising and quite concerning'

More than 1 of every 10 patients prescribed opioids for the first time became chronic users, the researchers found.

"It's a little surprising and quite concerning that such a large number of people who start these drugs are continuing them for such a long time," said study co-author Tara Gomes, a scientist at the Institute for Clinical Evaluative Sciences and St. Michael's Hospital in Toronto.

"It really suggests that patients and doctors need to reconsider whether or not there should be such broad use of long-term opioid therapy, particularly when often times patients aren't really seeing a lot of benefits."

As for why men and women differed, it could be that doctors are more inclined to prescribe higher doses to men, which leads to a domino effect of higher death rates among them, Gomes speculated.

It's also possible that men may not tolerate pain as well and ask for more pain relief than women.

Men are also more likely to have alcohol use disorders. Combining alcohol and opioids is risky.

The researchers called for more studies into the role of opioids in chronic noncancer pain and to see which patients can safely tolerate the drugs.

Limitations of the study include there was no reliable data on recreational drug use aside from alcohol use disorder and there was no information about receiving opioids from illicit sources or prescriptions paid in cash or through private coverage.

In 2010, guidelines for family doctors were published in the Canadian Medical Association Journal to try to curtail misuse of opioids and resulting overdose deaths.  

Opioid deaths now represent more than 40 per cent of all mortality from poisoning in North America, outnumbering deaths from alcoholic liver disease and HIV, the researchers said.

Opioids work by interfering with transmission of pain signals but can also produce a high by stimulating the brain's pleasure centres.

The study was funded by the Ontario Ministry of Health and Long-Term Care and ICES. One of the study authors has received honoraria from pharmaceutical companies.