It's a bad day when the federal health minister wants to check your work. But that's what's happening to a McMaster University committee that was assigned to develop new opioid-prescribing guidelines for Canada's doctors.

The rules from Health Canada were clear when it awarded the half-million-dollar grant to McMaster's Michael G. DeGroote National Pain Centre in 2015: No one with any ties to big pharma could be allowed to vote on the final draft of the guidelines, which were intended to help doctors make difficult decisions about opioid use for chronic non-cancer pain.

As the hand-picked experts sat around the table arguing about when doctors should prescribe the dangerous pills, everyone in the room assumed everyone else in the room was free of industry ties.

But the truth was revealed earlier this month, when the guidelines were finally published.

One of the members of the voting committee had ties to drug companies that sell opioids, including Purdue Pharma (Canada), which manufactured OxyContin, one of the most notorious prescription opioid drugs.

The guidelines on opioid-prescribing practices in Canada are now under review after it was revealed that a member of the voting committee had received financial compensation from Purdue Pharma Canada, as well as other companies that market such medications. (Douglas Healey/Associated Press)

Dr. Nav Persaud, another member of the voting committee, said he was shocked when he learned the news.

"We were asked to complete conflict-of-interest declaration forms twice," Persaud said. "My understanding was that the declarations were going to be reviewed, and anyone with financial conflicts of interest was going to be excluded from the voting panel."

Yet somehow Dr. Sol Stern, a family physician based in Oakville, Ont., was allowed to become a member of the voting committee, despite disclosing he had received financial compensation from Purdue and other companies that market opioids for giving talks and serving on company advisory boards.

The entire episode shines a light on an aspect of Canada's health-care system that is widely accepted, but rarely discussed — the vast financial relationships between doctors, hospitals and the pharmaceutical industry.

Nearly half of the pain specialists on the broader expert advisory committee (six of its 13 members) also disclosed ties to drug companies that make opioid pills.

'Messy grey zone'

Drug companies routinely pay Canadian doctors to give talks to other doctors about new drugs and medical devices. Companies also pay doctors honorariums to attend drug industry meetings and become members of industry advisory boards. And the most prominent and influential medical specialists — those considered "thought leaders" — are paid to become drug industry consultants.

It's an industry-physician relationship that only comes to light when doctors are asked to make official conflict-of-interest disclosures.

The sad part is, in retrospect, it's going to be impossible to say whether the recommendations would have been different if the makeup of the panel was different. - Dr. Nav Persaud , voting committee member

"Each year, Purdue Pharma (Canada) proudly contributes funding to a wide range of organizations across Canada," the company said in an email to CBC News.

This includes investments in education for health-care professionals "to ensure appropriate prescribing, dispensing and use of our medicines in line with guidelines and standards," along with "health and science education programs; disease awareness initiatives; community agencies and programing for the broader scientific and academic communities."

Purdue-funded education programs are accredited by the College of Family Physicians of Canada. Doctors attend the seminars to earn credits, which are required as part of their medical licences.

"These programs are developed by independent experts and accredited by the appropriate third party," Purdue said in the email.

One example of a Purdue-sponsored continuing medical education program was called "Optimizing Pain Relief While Reducing Risk: Finding Your Comfort Zone." It was presented to doctors across Canada in 2014. The College of Family Physicians of Canada has not responded to CBC's request for information about that course.

Dr. Benedikt Fischer, a senior scientist at Toronto's CAMH, says the drug industry's influence through medical education or unrestricted grants is subtle and hard to pin down.

"The industry sponsors a range of things that look beneficial, which, at the same time, may form a situation of bias that can be hard to pinpoint, but may influence people's thinking and interpretation of critical data," he said. "A lot of it happens in a messy grey zone."

Independent review

One clue that industry funding can influence judgement was Health Canada's original insistence that the opioid guidelines for chronic non-cancer pain be free from financial conflicts of interest.

"In the past, both in Canada and elsewhere, there have been concerns that some documents that have made recommendations to subscribers about how to treat pain have been influenced by industry, by people who make products to treat pain," Philpott told CBC News. She added that there have been cases where the information has not been accurate.

"It's obviously not the right way to get unbiased guidance to clinicians," she said. "And it was very important to us that the guidelines be established in a way that there would be no accusations that they would be seen to benefit the industry in any way."

Health Minister Jane Philpott on Thursday ordered an independent scientific review into the new opioid-prescribing guidelines. (Fred Chartrand/Fred Chartrand)

So did conflicts of interest affect the final version of the new opioid-prescription guidelines? That's what the health minister wants to find out.

She's asked the Canadian Institutes for Health Research to gather a group of "key stakeholders, including non-governmental organizations, academia and other partners" to review the new guidelines and evaluate whether they are solid and based on scientific evidence.

"The sad part is, in retrospect, it's going to be impossible to say whether the recommendations would have been different if the makeup of the panel was different," said Persaud. "Unfortunately, it's muddled now."

For its part, McMaster University defended the choice of experts for the guideline panel.

"The steering committee selected all members of the clinical expert committee, and we strove to include experts with a range of views on the role of opioids in the management of chronic pain, including those who viewed opioids as having an important role and others who viewed the practice of using opioids in this setting with extreme skepticism," committee spokesperson Jason Busse said in a statement.

"This was intentional and meant to ensure that we heard and considered the full range of opinions regarding opioids for chronic non-cancer pain."