Opioid maintenance: a comparative review of pharmacological strategies.

The use of opioids outside of medical practice is a significant health problem with important social and political implications. Although treatment of opioid dependence is traditionally focused on heroin users, there is increasing recognition that a large number of people become dependent through the use of prescription opioids. The necessity for long-term treatment has also been increasingly recognised. At present, there are several pharmacotherapies available for maintenance treatment, including drugs that are full agonists at the opioid receptor (e.g., methadone, slow-release oral morphine), a partial agonist (buprenorphine) and an opioid antagonist (naltrexone). This review examines the existing strategies, highlights problems associated with their use and discusses the opportunities for new treatment approaches, particularly the use of long-acting formulations.