An extended-release version of the anti-addiction medicine naltrexone reduces drinking in alcohol-dependent patients within two days of being injected, according to a new study.
Naltrexone blocks opioid receptors and is approved for use in alcohol-dependent patients. To improve adherence, "an intramuscular, injectable, extended-release formulation of naltrexone has been developed," Dr. Domenic A. Ciraulo, of Boston University School of Medicine, and colleagues explain in the Journal of Clinical Psychiatry.
The researchers tested injectable naltrexone XR in some 600 actively drinking, alcohol-dependent men and women who were given one of two doses of the drug or an inactive placebo every 4 weeks for 24 weeks. The participants also received 12 sessions of standardized, low-intensity psychosocial therapy.
Compared with the placebo patients, those given the higher dose of naltrexone had a significant reduction in the average daily number of drinks consumed by the second day. By the third day, fewer naltrexone patients reported heavy drinking compared with those on placebo (20 percent versus 35 percent, respectively). This reduction was maintained throughout the study.
While patients treated with the lower dose of naltrexone XR experienced reductions in these measures, the differences compared with placebo were not statistically significant.
Ciraulo's team is encouraged by the results. "Potential clinical implications of the rapid, early onset of effect of this medication's delivery system for patients who are dependent on alcohol include facilitation of early engagement in treatment, motivation to continue treatment, and focus on the goals established in counseling," they write.
