Monthly Injections of Naltrexone Show Continued Benefit in Treating Alcoholism

Paula Moyer, MA

June 01, 2005

June 1, 2005 (Atlanta) — Patients with alcohol dependence who continue taking naltrexone (Vivitrex) for a year or more continue to benefit from treatment, according to investigators who presented their findings here at the 2005 American Psychiatric Association Annual Meeting.

"We were pleased to see that [naltrexone] led to a sustained reduction in heavy drinking over an extended-treatment period," said principal investigator David Gastfriend, MD, in a presentation. The findings bode well for the treatment of alcoholism, which is a chronic disease characterized by relapses, Dr. Gastfriend said.

Dr. Gastfriend is the vice president of medical affairs at Alkermes, the maker of naltrexone, and a professor of psychiatry at Harvard Medical School in Boston, Massachusetts.

In a previous study, 624 patients with confirmed alcohol dependence participated in a 24-week, multicenter, double-blind, placebo-controlled study. The subjects had received six monthly injections of long-acting naltrexone at either 380 or 190 mg, or placebo. All patients also received psychosocial support that was consistent with the BRENDA approach. The BRENDA approach is an acronym for a manualized counseling strategy used in alcoholism treatment: (1) Biopsychosocial evaluation, (2) Report to the patient on the assessment, (3) Empathetic understanding of the patients problems, (4) Needs expressed by the patient that should be addressed, (5) Direct advice on how to meet those needs, and (6) Assessment of the responses and behaviors of patients, which are in turn used to advise and adjust treatment recommendations.

Among the 380 patients (61%) who completed the study, 332 (87%) enrolled in a one-year open-label extension. The 115 patients who had been randomized to 380 mg of naltrexone per monthly injection continued at that dose, and the 60 patients who received placebo injections were switched to 380-mg monthly injections of naltrexone. The remaining patients, who had been receiving 190-mg monthly injections, were switched to 380-mg monthly injections.

Of particular interest were the groups continuing at 380 mg per month, and the group switched to this dose from placebo. Those who continued at this dose had had a median of 2.6 days of heavy drinking per month in the first study and had a median of 1.6 such days per month in the extension, which were statistically insignificant in difference from each other. The investigators defined heavy drinking as five or more alcoholic drinks per day for men and four or more such drinks per day for women.

Among patients who were switched, the median number of heavy drinking days decreased from 5.2 days per month in the main trial when they received placebo injections to 1.8 days per month in the extension study when they were switched to active treatment (P < 0.01). Throughout the 18 months in both studies, patients tolerated treatment well, Dr. Gastfriend said. During the extension study, Dr. Gastfriend noted that the most common adverse events that investigators observed were headache, nasopharyngitis, and upper respiratory tract infections.

"This study is an important evaluation of the depot formulation of naltrexone," said Richard T. Suchinsky, MD, in an interview seeking outside commentary. "It is important to note, though, that this medication works for some patients but not for all. Physicians who are interested in using this medication to treat alcohol-dependent patients need to use it with that understanding."

Dr. Suchinsky is the associate chief for addictive disorders in the Department of Veterans Affairs in Washington, DC, and he is a corresponding member of the APA's Council on Addictions.

"We also need to remember that naltrexone is a useful adjunct that is intended to be used along with other treatments for alcoholism, such as counseling, support groups like Alcoholics Anonymous, and psychosocial support," Dr.Suchinsky said. "Used in this way, naltrexone can be an effective pharmacologic adjunct to treating alcoholism and is in this manner illustrative of the concept of psychosomatic medicine as a way to integrate psychiatry and medicine."

The study was funded by Alkermes, the maker of naltrexone.

2005 APA Annual Meeting: Abstract 280. Presented May 23, 2005.

Reviewed by Gary D. Vogin, MD


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