In my post of March 17, 2013, I reported that the European Medicines Agency EMA recently approved the long-acting opioid antagonist nalmefene for the treatment of alcohol dependence. In the current issue of Biological Psychiatry now Karl Mann from the Central Institute of Mental Health in Mannheim, Germany, and colleagues report in a “Priority Communication” on the results of the largest study to date of nalmefene in patients with alcohol dependence (Mann et al., 2013).604 patients were enrolled in the double-blind, randomized, placebo-controlled study. They were given either placebo or 18 mg of nalmefene for a period of 24 weeks. The substance was not administered as maintenance therapy, but on an as-needed basis, that means, patients were asked to take their medicine, if they felt at risk for the consumption of alcohol (preferably 1-2 hours before drinking). Although taking placebo had a profound effect, nalmefene reduced their alcohol consumption significantly more. In the placebo-treated group, the number of heavy drinking days dropped from 20 days/month before study entry to 11 days/month after six months. Nalmefene led to a reduction in the days of heavy drinking from 19 to 8 days/month. Adjusted to the different baseline level, there was a difference between the two treatments of 2.3 days (p = 0.0021). The average amount of alcohol consumed was 85 g of alcohol per day before treatment in the placebo group, it was reduced to 45 g/day after six months. In the nalmefene group the average alcohol consumption decreased from 84 g/day to 33 g/day. Baseline-adjusted this results in a significant difference of 11.0 g alcohol / day (p = 0.0003). A significant difference between the two treatments was already found after one month of treatment.
The study shows two things: First, that even a placebo treatment leads to a profound reduction in alcohol consumption, but this is even more pronounced with nalmefene. Second, and perhaps more important, that treatment of alcohol dependence does not necessarily need to have the goal of complete abstinence. With opiate antagonists, patients get drugs at hand that they can use when needed, i.e. when they feel the urge for alcohol.
In the same issue of Biological Psychiatry a commentary with the title „Naltrexone and Nalmefene: Any Meaningful Difference?“ by Robert Swift of Brown University in Providence, Rhode Island, is published (Swift, Biol Psychiatry 2013). He answers the question as follows: „The comparison of these two medications given the current state of knowledge and treatment evidence suggests that there are minimal if any differences in efficacy for reducing heavy drinking. In terms of adverse events, nalmefene may offer an advantage in no hepatotoxicity and the lack of need for liver function testing.“
This post is also available in: German