Toronto Public Health says demand for referrals to methadone clinics in the city has tripled in the last week, after the prescription painkiller OxyContin was discontinued.

"Normally, we would see maybe five or six people coming in in a week asking for methadone treatment, and now we're seeing about three times that number," said Dr. Rita Shahin, an associate medical officer of health. "It's hard to know how much OxyContin is still out there on the street and whether that demand for services will increase as more people are worried about going into withdrawal."

Shahin says another concern is addicts turning to other prescription painkillers, such as the fentanyl patch. Fentanyl is a much stronger opioid than OxyContin.

"Some drug users are actually scraping the medication off the patch," she said.

That makes it hard for even experienced drug addicts to estimate what kind of a dose they're getting, Shahin said. Guess wrong and a drug user could wind up overdosing or dead.

Officials worry about potential crime increase

Toronto Public Health is also concerned there may be an increase in crime as OxyContin becomes scarce on the street.

Near Queen Street and Spadina Avenue, one pharmacist is already taking precautions. Louis Hanna said his pharmacy is in the heart of a "methadone area" in downtown Toronto. He also has clients who have prescriptions for the new version of OxyContin, called OxyNeo.

Hanna said that since last November he's required prescription holders to show ID and sign for their drugs.

"These medications are locked in a safe place and I have the key. ... I put it in my pocket. I don't leave anything in the pharmacy."

Northern Ontario man dies

Experts say the changeover is causing problems for doctors as well, with the overdose of a northern Ontario man serving as a red flag for those who must switch patients to another opioid to control their chronic pain.

Their training in pharmaceutical equivalents may be inadequate or out of date, they say.

The man who died at some point during the last month cannot be identified for privacy reasons. He had been prescribed OxyContin for chronic pain and the drug was paid for under the Non-Insured Health Benefits program, the government plan for aboriginal people.

But because OxyNeo is also not covered by the program, the man's doctor switched him to another long-acting opioid.

The replacement opioid had been prescribed at too high a dose and the man appears to have died from an overdose, which usually involves respiratory failure.

"There was an apparent inadvertent or unintentional dose escalation," Dr. Michael Wilson, regional supervising coroner for northwestern Ontario, said Tuesday from Thunder Bay, Ont. "I spoke to the doctor and the doctor just basically said that it was a mistake."

Wilson has informed several professional medical bodies in Ontario about the case, with a warning to physicians to be cautious when swapping opioids.

Dr. Meldon Kahan, an addiction expert with the University of Toronto's family medicine department, said doctors have access to tables that show equivalent doses for different drugs, but physicians are not always trained in how to use them properly.

With files from The Canadian Press