Traditionally, abstinence has been regarded as the primary treatment goal for alcohol dependence, and current pharmacological treatments for alcoholism are approved only for relapse prevention. However, relapse rates remain high and a goal of abstinence is unacceptable to many patients. To address these concerns and provide opportunities for improved patient outcomes, new evidence-based treatments are necessary.
"Our new findings may mark a true paradigm shift in the treatment of men and women who suffer from alcohol related disorders. While abstinence should be the best bet, a reduction in consumption may be a valuable alternative for the many patients who cannot attain abstinence or are not (yet) capable of doing so," said Dr. Karl Mann at Central Institute of Mental Health in Germany, who led the research.
Mann and his colleagues conducted a clinical trial to investigate the effectiveness of nalmefene in reducing alcohol consumption. They recruited 604 alcohol-dependent patients, half of whom were randomized to receive nalmefene, while the other half received visually-identical placebo pills. Neither patients nor their doctors knew which treatment they were receiving. Patients were instructed to take one tablet on each day they perceived a risk of drinking alcohol, and were followed by the study investigators for 24 weeks.
What they found is promising. Nalmefene was significantly better than placebo in reducing alcohol consumption and it improved patients' clinical status and liver enzymes. It was also generally well-tolerated, with most side effects characterized as mild or moderate and quickly resolved.
"With nalmefene, we seem to be able to 'block the buzz' which makes people continue to drink larger amounts. With such a harm reduction approach, a new chapter in treating alcoholism could be opened," said Mann.
These findings provide evidence that "as-needed" prescription of nalmefene is an effective treatment for alcohol dependence. Unlike medications that must be taken every day, the as-needed approach targets medication administration to periods where alcohol use is more likely.
"It is encouraging to see the efficacy of nalmefene in this clinical trial. There is a need for more treatment options for the pharmacotherapy of alcoholism," said Dr. John Krystal, Editor of Biological Psychiatry
. "This study also provides support for 'as-needed' treatment, an approach that may be attractive to many patients. However, it flies in the face of the notion that daily treatment may protect people who are either ambivalent about treatment or unaware when they are particularly at risk for relapse."
The first medication developed for the treatment of alcohol dependence was naltrexone, an opioid receptor blocker. At therapeutic doses, it blocks most of the mu subtype of opioid receptors in the brain but it has lesser effects at the delta and kappa subtype of opioid receptors. Nalmefene is a newer opioid receptor modulator that has a subtly different profile at opioid receptor subtypes, with increased relative potency for kappa opiate receptors compared to its potency at mu opiate receptors. It was studied here because it has been shown to have potential for reducing alcohol consumption.
"It remains to be seen whether the differences between nalmefene and naltrexone at opioid receptors yield meaningful differences in their effectiveness," cautioned Krystal.
As with most studies, additional research is necessary, but this study provides strong evidence that nalmefene can provide an important clinical benefit for alcohol-dependent patients.