Varenicline has a good tolerability profile and is efficient in promoting smoking cessation.

In order to assess the safety and efficacy of Varenicline as a method for quitting smoking, an overview, meta-analysis, and trial sequential analysis were performed.

The inclusion criteria for this study encompassed systematic reviews and randomized controlled trials that compared Varenicline to placebo for smoking cessation. The effect size of the systematic reviews was summarized using a forest plot. To analyze the data, both trial sequential analysis and traditional meta-analysis were conducted utilizing trial sequential analysis 0.9 software, and Stata software, respectively. Lastly, the quality of evidence regarding the effectiveness of Varenicline in promoting abstinence was assessed utilizing the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach.

This comprehensive analysis included a total of 13 systematic reviews and 46 randomized controlled trials. Among the 12 review studies, Varenicline demonstrated superiority over placebo in promoting smoking cessation. The meta-analysis findings revealed a significant elevation in the likelihood of quitting smoking with Varenicline compared to placebo (odds ratio = 2.54, representing moderate quality evidence). Subgroup analysis indicated notable differences between smokers with underlying health conditions and the general smoking population.

Additionally, variations were observed in the follow-up durations of 12, 24, and 52 weeks. Common adverse events associated with Varenicline encompassed nasopharyngitis, indigestion, irritability, depression, headache, sleep disturbances, abnormal dreams, vomiting, and nausea. The trial sequential analysis results further supported the evidence of Varenicline's effectiveness in smoking cessation.

Varenicline outperformed placebo in helping individuals quit smoking. It exhibited mild to moderate adverse events, but overall, it had a good tolerability profile. To broaden the understanding, future studies should explore the effectiveness of Varenicline when used in conjunction with other smoking cessation strategies and compare it to alternative interventions.