1051 — Meta-Analysis of Naltrexone and Acamprosate for Treating Alcohol Use Disorders: When Are These Medications Most Helpful?
Maisel NC, Blodgett JC, Wilbourne PL, and Finney JW, Center for Health Care Evaluation, VA Palo Alto Healthcare System;
Recent VA treatment guidelines recommend incorporating pharmacotherapy (acamprosate and naltrexone) into treatment for patients with alcohol use disorders (AUDs). However, rates of adherence to this recommendation remain low, in part due to concerns about the efficacy of these medications. To address the issue of when each medication may be most efficacious, we conducted meta-analyses to test: (1) the differential efficacy of acamprosate and naltrexone for two disparate treatment outcomes (fostering abstinence versus reducing heavy drinking), and (2) the hypothesis that different ways of implementing the medications (required abstinence before treatment, detoxification before treatment, goal of treatment, length of treatment, dosage) will moderate treatment effects.
A systematic literature search of citation databases (e.g., PubMed, PsycInfo) and previous reviews identified 65 randomized, placebo-controlled, English-language clinical trials completed between 1970-2009 focused on acamprosate or naltrexone for the treatment of AUDs. Trained coders rated treatment characteristics and calculated effect sizes.
Acamprosate had larger effects than naltrexone on abstinence outcomes (approx. d = .30 versus d = .10). There was a trend for naltrexone to have somewhat larger effects than acamprosate on the reduction of heavy drinking and craving (approx. d = .20 versus d = .05). Next, we examined moderators of the main effect of each medication. For acamprosate, detoxification before medication administration was associated with greater abstinence. For naltrexone, a longer period of required abstinence before the trial was associated with reduced heavy drinking.
Differences emerged for the efficacy of each medication based on the type of outcome of interest and the way the medication was administered. Effect sizes for both medications tended to be small, suggesting that pharmacotherapy is only one line of treatment that may be useful for AUDs.
This meta-analysis highlights the need to better understand when pharmacotherapy for AUDs is most efficacious. Practitioners prescribing naltrexone and acamprosate should carefully consider the intended outcome of treatment (total abstinence versus reduction of heavy drinking) and incorporate strategies that are associated with beneficial results, such as starting the medication while patients have been detoxified and abstinent for several days.