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Study: Monthly naltrexone injection could overcome compliance problem in treating alcohol dependence

April 5, 2005 -- Because of problems with adherence to a daily oral dose of naltrexone, the effectiveness found in treating alcohol dependence with a once-a-month injection of naltrexone could improve long-term treatment outcomes, according to a study in the April 6 issue of the Journal of the American Medical Association (JAMA}.

Alcohol dependence is a major public health problem, which worldwide is the fourth leading cause of disability, according to background information in the article. Alcohol dependence is present in approximately 4 percent of the U.S. adult population, is common among primary care patients, and may contribute to more than 100,000 preventable deaths per year. The drug naltrexone has shown efficacy for treatment of alcohol dependence. However, adherence to daily oral doses can be problematic, and clinical acceptance and utility of oral naltrexone have been limited.

James C. Garbutt, M.D., of the University of North Carolina at Chapel Hill, N.C., and colleagues conducted a study to determine the efficacy and safety of a new formulation, which releases naltrexone for 1 month following a single injection, for treatment of alcohol dependence.

The 6-month, randomized, double-blind, placebo-controlled trial was conducted between February 2002 and September 2003 at 24 U.S. public hospitals, private and Veterans Administration clinics, and tertiary care medical centers. Of the 899 individuals screened, 627 who were diagnosed as being actively drinking alcohol-dependent adults were randomized to receive treatment and 624 received at least 1 injection. Participants received either an intramuscular injection of 380 mg. of long-acting naltrexone (n = 205), 190 mg. of long-acting naltrexone (n = 210), or a matching volume of placebo (n = 209), each administered monthly and combined with 12 sessions of low-intensity psychosocial intervention.

The researchers found that compared with placebo, 380 mg. of long-acting naltrexone resulted in a 25 percent decrease in the event rate of heavy drinking days and 190 mg. of naltrexone resulted in a 17 percent decrease. Sex and pretreatment abstinence each showed significant interaction with the medication group on treatment outcome, with men and those with lead-in abstinence both exhibiting greater treatment effects. Discontinuation due to adverse events (e.g. nausea, headache, fatigue) occurred in 14.1 percent in the 380-mg. and 6.7 percent in the 190-mg. group and 6.7 percent in the placebo group. Overall, rate and time to treatment discontinuation were similar among treatment groups.

"In summary, the results from this trial, with one of the largest samples ever treated with a medication for alcohol dependence, indicate that long-acting injectable naltrexone is well tolerated and is associated with a significant reduction in heavy drinking in a population of actively drinking patients. The long-acting formulation has the potential to improve intervention strategies for alcohol dependence by providing a predictable pharmacological foundation for treatment. In addition to their utility for alcohol dependence, long-acting formulations may prove to be an important treatment strategy for a variety of addictive disorders," the authors write.

Source: Journal of the American Medical Association

Posted: April 2005