Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment, blinding, and incomplete outcome data) and by imprecise results (few patients and wide confidence intervals).
A Cochrane review included 2 studies with a total of 137 subjects assessing varenicline. Smoking cessation rates after varenicline were significantly higher than placebo, at the end of treatment (RR 4.74, 95% CI 1.34 to 16.71; 2 trials, n=137). Only one trial reported follow-up at six months (RR 5.06, 95% CI 0.67 to 38.24; n=128). There was no study investigating the efficacy of varenicline used primarily for smoking reduction. There were no significant differences in psychiatric symptoms between the varenicline and placebo groups. Nevertheless, there were reports of suicidal ideation and behaviours from two people on varenicline.
Date of latest search: 10 January 2013