Comment: The quality of evidence is downgraded by study limitations (unclear allocation concealment and blinding in most studies) and by inconsistency (unexplained variability in results).
A Cochrane review included 24 RCTs with a total of 6915 participants. Compared to placebo, acamprosate was shown to significantly reduce the risk of any drinking (RR 0.86; 95% CI 0.81 to 0.91; 24 trials, n=6172); NNT 9.09 (95% CI 6.66 to 14.28) and to significantly increase the cumulative abstinence duration (mean difference MD 10.94; 95% CI 5.08 to 16.81; 19 trials, n=5224), while secondary outcomes (gamma-glutamyltransferase, heavy drinking) did not reach statistical significance. Diarrhea was the only side effect that was more frequently reported under acamprosate than placebo RD 0.11 (95% 0.09 to 0.13); NNTB 9.09 (95% CI 7.69 to 11.11). Effects of industry-sponsored trials RR 0.88 (95% 0.80 to 0.97) did not significantly differ from those of non-profit funded trials RR 0.88 (95% CI 0.81 to 0.96). In addition, the linear regression test did not indicate a significant risk of publication bias (p = 0.861).
A systematic review and meta-analysis assessed the efficacy of acamprosate or naltrexone in reducing lapse/relapse compared to placebo in the treatment of alcohol dependence and treatment discontinuation. 22 RCTs studied acamprosate (n=5236) and 27 RCTs naltrexone (n=4199). The risk of returning to any drinking at 6 months was significantly lower for acamprosate (RR 0.83, 95% CI 0.78 to 0.89). There was little difference in the risk of participants discontinuing treatment for any reason (RR 0.91, 95% CI 0.83 to 1.00) or due to adverse events (RR 1.30, 95% CI 0.96 to 1.75) for the acamprosate compared to placebo groups. For natrexone, the risk of individuals returning to any drinking at approximately 3 months was reduced significantly (RR 0.92, 95% CI 0.86 to 1.00), as was the risk of individuals relapsing to heavy drinking at 3 months (RR 0.85, 95% CI 0.78 to 0.93). There was no significant difference between naltrexone and placebo for the risk of individuals discontinuing treatment for any reason (RR 0.94, 95% CI 0.84 to 1.05), but. risk discontinuing treatment due to adverse events was higher (RR 1.72, 95% CI 1.10 to 2.70).