OxyContin, the widely prescribed painkiller, has overtaken crack cocaine as Ottawa's most commonly abused drug, a residential drug treatment centre says.

OxyContin is a slow-release form of oxycodone and similar to morphine in its effect and addictiveness. When the drug is chewed or crushed and inhaled, it produces a rapid "heroin-like effect euphoria," according to Health Canada.

Staff at Ottawa's Harvest House say OxyContin has surpassed crack cocaine as the most commonly abused drug. (CBC)

"It's a whole warm sensation throughout your body," said Jamie Walsh, a recovered OxyContin addict. "All your troubles, all your worries fade away."

Staff at the city's Harvest House, which has offered a variety of rehabilitation programs for more than 30 years, said that six years ago, most residents in the drug program were getting treatment for addiction to crack cocaine.

Now, OxyContin is the most common drug addiction among residents, and the trend is growing, said Chris Leduc, a member of the program staff at Harvest House. OxyContin, also known as "hillbilly heroin," is easy to obtain, which is the major reason it's become the narcotic of choice, he said.

"Anyone can go to a doctor and pretty well get a prescription if they have the right story," Leduc said.

In 2007-08, Ontario doctors prescribed $54 million in OxyContin.

Critics say the drug is given out too freely, a phenomenon related to double doctoring — people who visit multiple doctors complaining of pain symptoms to obtain the narcotic for resale purposes.

The OxyContin market is lucrative, with pills selling for about $4 each at a pharmacy, but often for 10 times that much on the street. Leduc said the high profit margin on the pills has led to more pharmacy robberies in the city, including two on the same night in late February..

"[The burglars] are not asking for cash," he said. "They're asking specifically for drugs, and the drug that they're most specifically asking for is OxyContin."

Anjali Baichwal, a spokeswoman for the Ontario College of Pharmacists, said OxyContin theft is an issue across the province.

"Unfortunately, it is something we've seen a lot of activity in," Baichwal said, adding that the college encourages pharmacists to work with their local police to try to prevent theft.

Between 2004 and 2009, more than 450 people are estimated to have died in Ontario from overdoses involving oxycodone.

In February 2009, the Ontario Health Ministry announced it would lead a national investigation into OxyContin use and its potential abuse. Last November, Deb Matthews, the provincial minister of health, said Ontario is looking to impose new guidelines for medical professionals prescribing the drug and introduce a tracking system to help curb double doctoring.