Addicts in Canada have figured out how to get around the new safety features of narcotic pain patches so they can use the drugs to get high, the National Post reported May 5.

Researcher Benedikt Fischer of the B.C. Center for Addictions Research and colleagues said that misuse of fentanyl pain patches, sold under the brand name Duragesic, has been linked to dozens of overdose deaths. To help prevent misuse, drug maker Ortho-McNeil replaced the fentanyl gel in the patches to storing the drug in a plastic matrix. But some users have learned that they can add vinegar and water to the patch and then soak or heat it to draw the drug out of the matrix in liquid form.

"This is bad news in many ways and ... I don't think anybody has a clear idea what to do about it," said Fischer.

The study found that more than half of the 25 street addicts studied in Toronto had injected fentanyl within the past three months.

The research was published March 31, 2008  in the journal Drug and Alcohol Review.