Opioid agonist maintenance therapies include methadone, a long-acting potent agonist at the mu opiate receptor sites, and buprenorphine, a potent long-acting compound that acts as a partial opioid agonist at mu receptor sites. An additional opioid agonist therapy, L-α-acetylmethadol (LAAM), has an extended duration of action and high intrinsic activity at the mu opiate receptor, but it has been removed from the U.S. market by its manufacturer because of the risk of cardiac arrhythmia.[1,2]
Opioid agonist maintenance therapy may be the primary tool available to engage an opioid-dependent individual in treatment because it relieves unpleasant withdrawal syndromes and craving associated with abstinence. The central and subjective effects of agonist therapies are generally more acceptable to opioid-dependent patients than the effects of antagonist therapies, which are used to counteract the reinforcing effects of opioids. Consistent with this, treatment adherence with agonist therapies is greater than that with antagonist therapies.
Maintenance treatment with methadone or buprenorphine is appropriate for patients with a prolonged history (> 1 year) of opioid dependence. The goals of treatment are to achieve a stable maintenance dose of opioid agonist and facilitate engagement in a comprehensive program of rehabilitation, which will often include psychosocial treatment.
A licensed practitioner must approve maintenance treatment enrollment for a patient before the patient can start receiving treatment from a medication unit (e.g., a physician’s office, pharmacy, or long term care facility). After a year of continuous maintenance treatment, patients may qualify to receive 7- to 14-day supplies of methadone to take home. In addition, after two years of continuous maintenance treatment, patients can qualify to take home 15- to 30-day supplies.