The drug which is used for long-term maintenance in opioid addiction

Maintenance Therapy After the detoxification phase is over, the patient is maintained on one of the following regimens: 1. Methadone maintenance (Agonist substitution therapy) 2. Opioid antagonists Opioid antagonists have been in use for a long time but they were either paial antagonists (such as nalorphine) or had to be administered parenterally (such as naloxone) Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 44