An Ontario First Nations leader says a catastrophe is looming with the decision to stop manufacturing the drug OxyContin.

Nishnawbe Aski Nation Chief Stan Beardy says thousands of residents of Ontario reserves are addicted to the drug, which is up to twice as strong as morphine. The organization, which represents 49 First Nation communities in northern Ontario, estimates close to half its members are addicted to OxyContin.

Health Canada says when the pill is chewed or crushed, then injected or inhaled, it produces a "heroin-like euphoria."

The company that produces OxyContin will stop manufacturing the drug in Canada at the end of the month.

Purdue Pharma Canada will replace OxyContin with a new formulation called OxyNEO, which is formulated to make abuse more difficult.

Beardy says addicts will go into withdrawal, and that scares him.

Benedikt Fischer of the Centre for Applied Mental Health and Addictions at B.C.'s Simon Fraser University says there will be a lot of sick people.

He says without treatment to help deal with the addiction, a public-health catastrophe is imminent.

Withdrawal a 'miserable and prolonged illness'

Dr. David Juurlink, an internist and head of the division of clinical pharmacology and toxicology at Sunnybrook Health Sciences Centre in Toronto, said there are two ways to abuse long-acting opioids such as OxyContin.

The maker of OxyContin has decided to stop manufacturing the drug in Canada, which has some First Nations leaders concerned. (CBC)

One way is to take the tablet intact, and these users can continue using the new formulation in exactly the same way. But those who have been crushing the drug, for injection or inhalation, will not be able to use OxyNeo, he said.

For chronic OxyContin users to stop, they will either have to replace it with something else or go into withdrawal, Juurlink said.

"That will be quite a miserable and prolonged illness," he told CBC News.

Withdrawal affects people differently, but it typically lasts for several days, Juurlink said.

"It's horrible. Imagine the worst flu you have ever had multiplied by 20," he said. "Severe nausea and vomiting and diarrhea and disabling abdominal pain are just part of the symptoms these patients go through."

Support available for withdrawal issues: Health Canada

Health Canada said Friday it was possible that those who accessed OxyContin without a prescription could go into withdrawal.

"There is little concern of withdrawal for clients switching therapy from OxyContin to OxyNeo when taken as prescribed by a physician. However, it is possible that some clients who obtained OxyContin through other sources may go into withdrawal when OxyContin is removed from the Canadian market and they are unable to find another source of supply," Health Canada said in a statement Friday.

"This is a concern for any individual who obtains and uses OxyContin outside of appropriate medical indications."

Josh Fisher, a member of Long Lake 58 First Nation in northwestern Ontario, developed his OxyContin addiction in Thunder Bay.

"Finding, getting the means to get more was my one and only objective, day to day, from the time I woke up to the time I passed out," Fisher recalled. The 28-year-old has since quit the drug, with help from Narcotics Anonymous.

Dr. Claudette Chase, a family doctor who works on the Eeabmatoong First Nation in northern Ontario, said that without additional support to help with an imminent rise in patients suffering from OxyContin withdrawal, an already desperate situation will get out of control.

Chase predicts potentially upwards of 9,000 people will be withdrawing, while an already overworked medical staff in the north struggles to keep up.

"You respond to an epidemic as if it were an epidemic," she said. "When it was H1N1, there were extra nurses, there were flu clinics all over the north — help."

A crisis could also be turned around, provided the federal government responds in the best manner, Chase said. For instance, the provision of mobile treatment programs entering communities for weeks at a time could help people beat their addictions.

"What we lack right now is the human resources and financial resources to get them there," Chase said.

With the right kind of support, she hopes the absence of OxyContin will turn out to be the catalyst people need to get on the road to recovery.

Patients will qualify for OxyNeo

Patients who currently qualify for OxyContin coverage under the Non-Insured Health Benefits program will still have access to OxyNeo, Health Canada said. This program provides First Nations with health-related goods and services that are not insured by provinces and territories or other private insurance plans.

Health Canada said there is support available through the NIHB program for those dealing with withdrawal issues.

The program provides coverage for methadone and suboxone, which are drugs that are used for the treatment of opioid withdrawal, it said. Methadone is available and reimbursed under the program with no, or minimal, restriction. Suboxone is available for those who cannot take methadone due to conflicting medical conditions.

However, Health Canada said it recognized that limited access to methadone, particularly in remote communities, could be a problem.

"In such instances, the NIHB Program reviews requests from health providers on a case-by-case basis and will provide coverage for suboxone to help ensure First Nations clients have access to this drug without leaving their community," it said.