Suppression of Alcohol Dependence Using Baclofen: A 2-Year Observational Study of 100 Patients

The past decade has seen an expansion of research and knowledge on pharmacotherapy for the treatment of alcohol dependence. The Food and Drug Administration (FDA)-approved medications naltrexone and acamprosate have shown mixed results in clinical trials. Oral naltrexone and naltrexone depot formulations have generally demonstrated efficacy at treating alcohol dependence, but their treatment effect size is small, and more research is needed to compare the effects of different doses on drinking outcome. Acamprosate has demonstrated efficacy for treating alcohol dependence in European trials, but with a small effect size. In U.S. trials, acamprosate has not proved to be efficacious. Research continues to explore which types of alcohol-dependent individual would benefit the most from treatment with naltrexone or acamprosate. The combination of the two medications demonstrated efficacy for treating alcohol dependence in one European study but not in a multi-site U.S. study. Another FDA-approved medication, disulfiram, is an aversive agent that does not diminish craving for alcohol. Disulfiram is most effective when given to those who are highly compliant or who are receiving their medication under supervision. Of the non-approved medications, topiramate is among the most promising, with a medium effect size in clinical trials. Another promising medication, baclofen, has shown efficacy in small trials. Serotonergic agents such as selective serotonin reuptake inhibitors and the serotonin-3 receptor antagonist, ondansetron, appear to be efficacious only among certain genetic subtypes of alcoholic. As neuroscientific research progresses, other promising medications, as well as medication combinations, for treating alcohol dependence continue to be explored.

The gamma-aminobutyric acid (GABA(B)) receptor agonist, baclofen, has recently been shown to reduce alcohol intake in alcohol-preferring rats and alcohol consumption and craving for alcohol in an open study in humans. The present study was aimed at providing a first evaluation of the efficacy of baclofen in inducing and maintaining abstinence and reducing craving for alcohol in alcohol-dependent patients in a double-blind placebo-controlled design. A total of 39 alcohol-dependent patients were consecutively enrolled in the study. After 12-24 h of abstinence from alcohol, patients were randomly divided into two groups. Twenty patients were treated with baclofen and 19 with placebo. Drug and placebo were orally administered for 30 consecutive days. Baclofen was administered at the dose of 15 mg/day for the first 3 days and 30 mg/day for the subsequent 27 days, divided into three daily doses. Patients were monitored as out-patients on a weekly basis. At each visit alcohol intake, abstinence from alcohol, alcohol craving and changes in affective disorders were evaluated. A higher percentage of subjects totally abstinent from alcohol and a higher number of cumulative abstinence days throughout the study period were found in the baclofen, compared to the placebo, group. A decrease in the obsessive and compulsive components of craving was found in the baclofen compared to the placebo group; likewise, alcohol intake was reduced in the baclofen group. A decrease in state anxiety was found in the baclofen compared to the placebo group. No significant difference was found between the two groups in terms of current depressive symptoms. Baclofen proved to be easily manageable and no patient discontinued treatment due to the presence of side-effects. No patient was affected by craving for the drug and/or drug abuse. Baclofen proved to be effective in inducing abstinence from alcohol and reducing alcohol craving and consumption in alcoholics. With the limits posed by the small number of subjects involved, the results of this preliminary double-blind study suggest that baclofen may represent a potentially useful drug in the treatment of alcohol-dependent patients and thus merits further investigations.

Percent subjects with no heavy drinking days (PSNHDDs), an efficacy end point recommended by the Food and Drug Administration, considers abstinent individuals or those engaging in low-risk drinking behavior as successful responders to treatment. As PSNHDD has been used infrequently in previous alcohol clinical trials, we evaluated the utility and validity of the PSNHDD outcome measure in 2 large alcohol clinical trials. Data sets from 2 alcohol trials, COMBINE and a multisite topiramate trial, were used to analyze PSNHDDs and other traditional end points for the topiramate, naltrexone, acamprosate, and placebo groups. Effect sizes of PSNHDDs were determined for each month of active treatment and by varying grace periods-early periods in the trial where outcome is not considered in the analysis-and were compared with that of other traditional outcome measures. Long-term outcomes were compared for groups that had no heavy drinking days versus those that had heavy drinking days during active treatment. PSNHDD effect sizes were significant for both topiramate (0.34 and 0.25 at months 2 and 3, respectively) and naltrexone (0.24 and 0.26 at months 3 and 4, respectively). Given a 2-month grace period for naltrexone, the effect size of PSNHDDs was comparable to the effect sizes using traditional outcome measures. With a 1-month grace period for topiramate, it was greater than the majority of traditional outcome measures. Little is gained by allowing up to 1, 2, or 3 heavy drinking days as an end point. Subjects with no HDDs during treatment fared better than those with some HDDs on drinking outcomes and alcohol-related consequences during a 1-year follow-up. PSNHDD appears to be a clinically informative end point measure, especially when used with a grace period, and is as sensitive as most traditional outcome measures in detecting differences between the medication and placebo groups. Nonetheless, these findings should be replicated in other clinical data sets, particularly with medications that work via different mechanisms. Copyright © 2010 by the Research Society on Alcoholism. No claim to original U.S. government works.