A Cochrane review [Abstract] 1 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.
A secondary analyses of safety and efficacy outcomes by psychiatric diagnosis in EAGLES (Evaluating Adverse Events in a Global Smoking Cessation Study), a 12-week, randomized, double-blind, triple-dummy, placebo- and active (NRT)-controlled trial 2 of varenicline and bupropion with 12-week follow-up, in a subset population with a psychiatric disorder (n = 4092). Primary end-point parameters were incidence of prespecified moderate and severe neuropsychiatric adverse events (NPSAEs) and weeks 9 to 12 continuous abstinence rates. The observed NPSAE incidence across treatments was 5.1% to 6.3% in those with a psychotic disorder (n=390), 4.6% to 8.0% in those with an anxiety disorder (n = 792), and 4.6% to 6.8% in those with a mood disorder (n = 2910). Neither varenicline nor bupropion was associated with significantly increased NPSAEs relative to NRT or placebo in the psychiatric cohort or any psychiatric diagnostic subcohort. There was a significant effect of treatment on continuos abstinence (P < 0.0001) and no significant treatment-by-diagnostic subcohort interaction (P = 0.24). Abstinence rates with varenicline were superior to bupropion, NRT, and placebo, and abstinence with bupropion and NRT was superior to placebo. Within-diagnostic subcohort comparisons of treatment efficacy yielded estimated odds ratios for 9-12 abstinence rates versus placebo of greater than 3.00 for varenicline, greater than 1.90 for bupropion, and greater than 1.80 for NRT for all diagnostic groups.
Date of latest search: 21 December 2019
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