Background: the average prevalence of herbals use in the general population of the UK is 37.1%, and herbals are ranked as the most popular type of complementary and alternative medicine. The reasons for this popularity are complex, but presumed safety and effectiveness might play a role. Kudzu (Pueraria lobata) is a popular herb used in traditional medicine because of its alleged anti-dipsotropic mode of action.
Objectives: to assess kudzu for reducing alcohol consumption and alcohol addiction/dependence. The secondary objective was to evaluate the safety of kudzu.
Methods: we searched seven databases from their inception to January 2019 to identify potentially relevant studies. Two review authors independently used the Cochrane 'Risk of bias' tool to assess the risk of bias. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines while planning and reporting the results of this review. Two authors assessed the quality of the evidence using GRADE criteria: limitations of studies (risk of bias), inconsistency of results, indirectness of the evidence, imprecision and publication bias, downgrading where appropriate. We did this for primary and secondary outcomes.
Results: seven randomized controlled trials (RCTs) met the eligibility criteria. Most were small and had an unclear risk of bias. Four RCTs favoured kudzu over placebo in reducing number of drinks, normalizing drinking behaviour and increasing days of abstinence. A meta-analysis of three trials showed that compared with placebo, kudzu may reduce alcohol cravings (odds ratio (OR) 2.97, 95% confidence interval (CI) 1.37 to 6.46; heterogeneity: Tau² = 0.00; Chi² = 0.10, df = 2 (P = 0.95); I² = 0%, moderate-certainty evidence). All trials reported adverse effects, and three reported that none occurred following the administration of kudzu. In two RCTs, the frequency of adverse effects ranged from 1.7% to 3%, with headaches being the most common.
Conclusions: there is some evidence to support the effectiveness of kudzu for reducing alcohol cravings. However, the overall quality of the evidence was moderate, which warrants larger, better designed and adequately powered studies to provide a definite answer about the efficacy of this treatment. Such trials should also be preceded by more detailed study of potential mechanisms through which kudzu is expected to achieve its favourable effects. Although kudzu appears to be generally safe, and no serious adverse effects were reported in the included RCTs, further research into its safety is needed.
Patient or healthcare consumer involvement: none.