Antagonist Treatment for Opioid Dependence: Promise and Hurdles

Relapse rates among treatment-seeking opioid-addicted individuals are extremely high but can be markedly reduced by agonist-based maintenance therapies such as methadone or buprenorphine. However, these therapies are not always available due to a limited number of providers, waiting lists to access treatment, or laws that prevent their use. In addition, some persons do not want agonist-based therapy because they do not like its subjective effects, tried it with less than optimal results, and had trouble stopping it when they felt ready or because family or other external pressures oppose it. For these individuals, antagonist-based therapy can fill an important niche, particularly when administered as an extended-release formulation that blocks opioid effects for several weeks or months, thus offering protection from the adverse effects of opioid use including overdose and giving the patient a chance to begin working on lifestyle changes that are necessary to work toward sustained remission. This paper will review existing findings on naltrexone for opioid addiction treatment. Antagonist treatment, particularly when delivered as an extended-release formulation, is a meaningful addition to current treatment options for opioid-dependent patients who do not want or do not have easy access to agonist or long-term residential treatment. Genetic analysis might be useful for determining potential responders to naltrexone treatment of opioid dependence but additional studies are needed.