Evaluation of the effectiveness of cytisine for the treatment of smoking cessation: A systematic review and meta-analysis.

Background And Aims: Smoking is considered the main cause of preventable death world-wide. This study aimed to review the efficacy and safety of cytisine for smoking cessation.

Methods: This review included an exhaustive search of databases to identify randomized controlled trials (RCTs) in health centers of any level with smokers of any age or gender investigating the effects of cytisine at standard dosage versus placebo, varenicline or nicotine replacement therapy (NRT).

Results: We identified 12 RCTs. Eight RCTs compared cytisine with placebo at the standard dose covering 5922 patients, 2996 of whom took cytisine, delivering a risk ratio (RR) of 2.25 [95% confidence interval (CI) = 1.42-3.56; I  = 88%; moderate-quality evidence]. The greater intensity of behavioral therapy was associated directly with the efficacy findings (moderate-quality evidence). The confirmed efficacy of cytisine was not evidenced in trials conducted in low- and middle-income countries. We estimate a number needed to treat (NNT) of 11. Two trials compared the efficacy of cytisine versus NRT, and the combination of both studies yields modest results in favor of cytisine. Three trials compared cytisine with varenicline, without a clear benefit for cytisine. Meta-analyses of all non-serious adverse events in the cytisine group versus placebo groups yielded a RR of 1.24 (95% CI = 1.11-1.39; participants = 5895; studies = 8; I  = 0%; high-quality evidence).

Conclusions: Cytisine increases the chances of successful smoking cessation by more than twofold compared with placebo and has a benign safety profile, with no evidence of serious safety concerns. Limited evidence suggests that cytisine may be more effective than nicotine replacement therapy, with modest cessation rates.