A study in the current Archives of General Psychiatry (Volume 56, pages 719-724) shows that nalmefene, an opioid antagonist that is not now commercially available in the oral form studied, is effective in preventing relapse to heavy drinking in alcohol dependent individuals. Barbara J. Mason, Ph.D., and colleagues at the University of Miami School of Medicine found from a 12-week double-blind, placebo-controlled clinical trial that patients who received nalmefene were 2.4 times less likely to relapse to heavy drinking than those who received a placebo.
"This study again demonstrates the promise of pharmacologic agents to work with standard behavioral treatments in the treatment of alcoholism. Prospects for improving treatment outcome have never been better," said Enoch Gordis, M.D., Director, National Institute on Alcohol Abuse and Alcoholism, a component of the National Institutes of Health.
Naltrexone, another opioid antagonist that is selective for the mu receptor, was approved by the U.S. Food and Drug Administration in 1994 for use in alcoholism treatment. The newer nalmefene is a "universal" opioid antagonist that works on all opioid receptors.
Men and women aged 18-65 years who met Diagnostic and Statistical Manual, Third Edition, Revised criteria for alcohol dependence participated in the study. Dr. Mason and her colleagues randomly assigned 105 of the 162 individuals screened to oral nalmefene at a dose of either 20 mg or 80 mg per day, or to placebo. All patients received professionally delivered, manual-guided, cognitive-behavioral therapy designed to increase their ability to avoid or cope with high-risk situations that can precipitate drinking.
The researchers found no significant differences between the 20 mg and 80 mg nalmefene groups and, therefore, presented their results as nalmefene versus placebo comparisons. Although one-third of the nalmefene patients relapsed to heavy drinking at least once during the 12-week trial, significantly more nalmefene than placebo patients altogether avoided relapse. Of patients who relapsed, those on nalmefene had fewer subsequent heavy-drinking episodes. Patients on nalmefene showed no evidence of medically serious adverse drug experiences and had high rates of medication compliance and treatment completion. The nalmefene and placebo groups did not differ in rates of abstinent days or self-reported craving severity.
"Alcohol consumption is mediated by multiple neurotransmitters and neuromodulators, including nonopioid systems, so that an opioid antagonist alone would not necessarily eliminate alcohol drinking in all alcohol dependent persons," said Dr. Mason. "But any agent that can reduce relapse would be a useful addition in treating alcoholic patients, approximately one-half of whom relapse within the first few months of most behavioral treatments." Several pharmaceutical companies have approached the University of Miami to review the nalmefene data in support of a new drug application to the FDA, Dr. Mason said.
"As neuroscience research advances knowledge of how alcohol acts on the brain, that knowledge will continue to be applied to develop new medications," said Richard Fuller, M.D., Director, Division of Clinical and Prevention Research, NIAAA. "Medications development is a top NIAAA priority."
"A Double-Blind, Placebo-Controlled Study of Oral Nalmefene for Alcohol Dependence" was conducted at the University of Miami School of Medicine Alcohol Disorders Research Clinic, Jackson Memorial Medical Center, Miami, Florida, with support from NIAAA. Through grants to researchers in medical and academic institutions, NIAAA supports an estimated 90 percent of alcohol research conducted in the United States.
To arrange an interview with Dr. Mason, contact Judy Lozano (telephone 305/243-4059). To arrange an interview with Dr. Gordis or Dr. Fuller or for additional alcohol research information, contact NIAAA Press (telephone 301/443-3860) or visit http://www.niaaa.nih.gov/.