Efficacy of Varenicline in the Treatment of Alcohol Dependence: An Updated Meta-Analysis and Meta-Regression

Background: Although varenicline has been used for alcohol dependence (AD) treatment, its efficacy for this condition remains controversial. Aims: This systematic review and meta-analysis of randomized controlled trials (RCTs) assesses the efficacy and safety of varenicline in patients with AD. Methods: PubMed, Cochrane Library, ScienceDirect, Web of Science, and ThaiLis were systematically searched. RCTs investigating the efficacy and safety of varenicline in patients with AD were included. Study selection, data extraction, and quality assessment were independently performed by two authors. The Jadad score and Cochrane risk of bias were used to assess the quality of the included studies. Heterogeneity was assessed using I(2) and chi-squared tests. Results: Twenty-two high-quality RCTs on 1421 participants were included. Varenicline significantly reduced alcohol-related outcomes compared with placebo based on percentage of abstinent days (standardized mean difference [SMD] 4.20 days; 95% confidence interval [CI]: 0.21, 8.19; p = 0.04), drinks per day (SMD −0.23 drinks; 95% CI: −0.43, −0.04; p = 0.02), drinks per drinking day (SMD −0.24 drinks; 95% CI: −0.44, −0.05; p = 0.01), craving assessed using the Penn alcohol craving scale (SMD −0.35; 95% CI: −0.59, −0.12; p = 0.003), and craving assessed using the alcohol urge questionnaire (SMD −1.41; 95% CI: −2.12, −0.71; p < 0.0001). However, there were no significant effects on abstinence rate, percentage of drinking days, percentage of heavy drinking days, alcohol intoxication, or drug compliance. Serious side effects were not observed in the varenicline or placebo groups. Conclusion: Our results indicated that AD patients treated with varenicline showed improvement in percentage of very heavy drinking days, percentage of abstinent days, drinks per day, drinks per drinking day, and craving. However, well-designed RCTs with a large sample size and long duration on varenicline treatment in AD remain warranted to confirm our findings.