"Even though opioids have been controlled in the United States with regulations and restrictions, opioid utilization has been increasing at an unprecedented pace (1-10). Manchikanti et al (1), in an evaluation of opioid usage over a period of 10 years, showed an overall increase of 149% in retail sales of opioids from 1997 to 2007 in the United States, with an increase of 1,293% for methadone, 866% for oxycodone, and 525% for fentanyl. Similarly, the increase in therapeutic opioid use in the United States in milligrams per person from 1997 to 2007 increased 402% overall, with the highest increase in methadone of 1,124% mg/person and oxycodone of 899% mg/person."

Source

Christo,Paul J.; Manchikanti, Laxmaiah; Ruan, Xiulu; Bottros, Michael; Hansen, Hans; Solanki, Daneshvari R.; Jordan, Arthur E.; and Colson, James , "Urine Drug Testing In Chronic Pain," Pain Physician (Paducah, KY: American Society of Interventional Pain Physicians, March/April 2011), Vol. 14, Issue 2.