FRIDAY, Nov. 24 (HealthDay News) -- Heroin use in Canada has declined, and prescription opioids such as morphine, OxyContin or Dilaudid now make up the biggest share of illicit opioid use, note researchers in the current Canadian Medical Association Journal.

A team led by Benedikt Fischer, of the University of Victoria, in British Columbia, analyzed data from the OPICAN study, a multi-site examination of drug use patterns among opioid users across Canada.

The researchers said their findings have several implications.

They noted that people who use prescription opioids illegally usually obtain the drugs directly or indirectly (i.e., through partners or friends) from sources within the medical system. Changes may be needed in the way that opioid addiction treatment programs are managed, the researchers suggested.

The study was prompted by reports of substantial increases in prescription opioid abuse in Canada.

More information

The American Academy of Family Physicians has more about opioid addiction.