Methadone is a synthetic opioid, used medically as an analgesic and in the treatment of narcotic addiction. It was developed in Germany in 1937, and in the USA was first brought to market by the pharmaceutical company Eli Lilly and Company. Methadone is increasingly being prescribed by doctors as a pain medication and abused by drug users searching for a cheap, easy way to get high, physicians and federal drug officials say.
Methadone can linger in body tissue for an unusually long time — 24 to 59 hours in some cases. Sometimes users assume it has worn off, then take other drugs or more methadone, leading to respiratory depression, coma and eventual death. Here is the methadone factsheet from White House Drug Policy.
Truly an ironic turn in the history of methadone, which for years has been used to treat heroin addiction.