Isn it illegal in the United States for any addict to be maintained on an opioid drug outside of an approved methadone program?
That was true, with the exception of specially exempted or experimental programs, for the past 80 years. However the Drug Addiction Treatment Act of 2000 modified the law to permit qualified and registered physicians to prescribe certain opioids for maintenance or detoxification. As of this time, the only opioid permitted to be prescribed under this law is buprenorphine, and then only in the approved formulations of Subutex and Suboxone.