Powerful but misleading marketing that for years pushed the highly addictive painkiller OxyContin has left potentially tens of thousands of Canadians with the burden of addiction, critics claim.

OxyContin helped transform the medical landscape after it was introduced in the late 1990s, touted by doctors and pitched as a less addictive alternative to other opioids.

Cancer patients and others suffering from chronic pain considered the pill — twice as strong as morphine — to be a godsend.

But the CBC's The Fifth Estate found that as soon as several provinces dropped OxyContin this year as a publicly funded medication and it vanished from shelves, the drug once praised as a blessing became a curse for some addicts.

Unknown to some doctors and pharmacists when OxyContin debuted were its extremely addictive properties, a fact that may have contributed to its becoming an international best-selling painkiller.

OxyContin was taken off the Canadian market this month. To replace the drug, Purdue Pharma, the company that makes OxyContin, began manufacturing a new formulation called OxyNeo. The replacement pill can't be crushed or liquefied and has thus been promoted as less prone to abuse. There are otherwise no clinical differences between the two brand names.

Several provinces have also announced OxyNeo will not be covered by public funds and will restrict access.

Drugmaker guilty of misleading public

In 2007, three executives with the American branch of Purdue Pharma pleaded guilty in a U.S. federal court to misleading regulators and an unsuspecting public about risk of addiction to OxyContin. The firm agreed to pay more than $600 million in civil and criminal fines.

OxyContin sales in Canada nevertheless rocketed to more than $240 million in 2010 from $3 million in 1996.

'When you run out, you'll do anything because that sickness — you can't compare it to even the worst flu you've had.'—Tammy Dagnell, OxyContin addict

Marty Whittaker, who broke her back water-skiing 12 years ago, is among 30,000 people in Ontario whose OxyContin prescriptions will soon run out because of the province's decision to stop covering the drug in its public plan.

Now she's bracing for a painful adjustment to a world without a pill she's grown dependent on.

"It's the only medication — oral medication — that we've tried that deals effectively with my pain," Whittaker said.

"I'm as dependent on OxyContin as I am on my glasses to see."

Dr. John Craven, who runs a methadone clinic, blamed what he sees as an escalating addiction epidemic on irresponsible doctors who bought into the multimillion-dollar pharmaceutical sales campaign.

'Reckless disregard for safety'

"I think it's been reckless prescribing," Craven said. "I think they've forged ahead with complete and reckless disregard for the safety and vulnerability of the people in our communities."

Addiction clinics are expecting an influx of visitors seeking help as OxyContin supplies disappear from pharmacies. Last week, Toronto Public Health officials recorded a threefold spike in demand for methadone treatments.

Tammy Dagnell, who started taking OxyContin for chronic pain in 1997, knows how hard it is to quit. She's been trying to kick the habit for years.

"When you run out, you'll do anything because that sickness — you can't compare it to even the worst flu you've had," she said. "It's an absolute addiction, of course, but the chemistry in OxyContin, it does help your pain."

The Fifth Estate contacted Purdue Pharma for an interview but only received a written statement that said all the company's sales activities in Canada complied with government regulations.