"The large contribution to mortality from oxycodone and methadone may be because of the long duration of action of methadone and OxyContin. Drug users may accidentally overdose by overlapping doses when the desired euphoric or analgesic effect is slow in coming. Abusers have learned to ingest and inject pulverized OxyContin pills, defeating the controlled-release mechanism and releasing dangerous amounts of the drug within a short time."

Source

Paulozzi, Leonard J., "Opioid Analgesic Involvement in Drug Abuse Deaths in American Metropolitan," American Journal of Public Health (Vol 96, No. 10), October 2006, p. 1756.
http://www.ncbi.nlm.nih.gov/p…