The Declining Efficacy of Naltrexone for Alcohol Use Disorders Over Time: A Multivariate Meta-Analysis
Naltrexone is an approved oral medication to treat alcohol-use disorders. While naltrexone has been found to be an effective form of treatment, some studies showed that its effectiveness has decreased over time.
Del Re and colleagues examined whether previous findings about the efficacy of naltrexone on relapse to heavy drinking and percent days drinking were smaller in more recent studies and whether being a multicenter or single-site study had an impact on the effectiveness of naltrexone by performing a meta-analysis. The researchers looked at publication year, multicenter design (whether the study was conducted at one or multiple locations), and whether a placebo was used at the beginning of the study before naltrexone was prescribed.
The authors found small but significant effects of naltrexone relative to placebo for both relapse to drinking and percent days abstinent.
Naltrexone had a larger effect in reducing heavy drinking than in promoting abstinence.
The results from this study align with the results from a previous study where a significant decrease in naltrexone’s effects on relapse to heavy drinking was found. Publication year was statistically significant for both outcomes, with more recent studies having smaller effect sizes. The authors postulate that this could be due to stricter study protocols and designs being used.
The researchers found that:
- multicenter studies did not have smaller effects on either drinking outcome compared to single-site studies (however, this difference could be due to differences in methodology used between the original study and the study performed by Del Re and colleagues).
- having a period during which a placebo is prescribed before naltrexone is given, did not impact the effectiveness of naltrexone on either outcome
- naltrexone effect sizes have decreased over time (however, this study was unable to determine exactly why).
Alcohol use disorder is highly prevalent and costly medical condition. It is also heavily stigmatized such that many who suffer do not seek specialty care for their alcohol addiction. Because studies have found that alcohol use disorder can often be managed on an outpatient basis with medications (naltrexone) and non-specialist clinical providers (e.g., primary care physicians), more individuals suffering from alcohol use disorders could gain access to care, with treatment being conducted at the primary care setting level.
While not a silver bullet, medications like naltrexone can help many more people begin to get a foot in the door of the recovery process.
Del Re, A. C., Maisel, N., Blodgett, J., & Finney, J. (2013). The declining efficacy of naltrexone pharmacotherapy for alcohol use disorders over time: a multivariate meta‐analysis. Alcoholism: Clinical and Experimental Research, 37(6), 1064-1068.