Is the combination of varenicline (Chantix) and sustained-release bupropion (Zyban) superior to varenicline alone for increasing smoking cessation rates in adult smokers?
Combination therapy with varenicline and sustained-release bupropion was associated with a significantly higher prolonged abstinence rate compared with varenicline monotherapy at 12 weeks and 26 weeks in adult smokers attempting to quit. By 52 weeks, however, the difference was no longer statistically significant. Adverse events, particularly anxiety and depression, were significantly more common in the combination therapy group. Combination therapy was significantly more successful for achieving prolonged abstinence at 12, 26, and 52 weeks among heavy smokers (at least 20 cigarettes daily; number needed to treat = 8.6; 95% confidence interval, 4.6 to 71.6). (Level of Evidence = 1b)
These investigators identified adults (N = 506), 18 years or older, who reported smoking at least 10 cigarettes per day for at least six months and who were in otherwise good health. Patients randomly received (concealed allocation assignment) varenicline plus bupropion SR (combination therapy), or varenicline plus matching placebo (monotherapy) in standard recommended doses. The study protocol consisted of a telephone screening call, 11 brief clinic visits, and three follow-up telephone calls. Individuals masked to treatment group assignment assessed outcomes on the basis of patient self-reported tobacco cessation in the previous seven days, which was confirmed by an exhaled carbon monoxide level of less than 9 parts per million. Complete follow-up occurred for 62% of patients at 52 weeks. Participants who discontinued the study and for whom no further information on smoking behavior was available were considered to have relapsed at the time of dropout.
Using intention-to-treat analysis, combination therapy was associated with a significantly higher prolonged abstinence rate at 12 weeks and 26 weeks compared with monotherapy, but by 52 weeks the difference was no longer statistically significant. There was no difference in weight gain between the two groups, but adverse events—particularly anxiety and depression—were significantly more common in the combination therapy group. No differences were observed to show any treatment effects according to age or sex, but combination therapy was significantly more successful for achieving prolonged abstinence at 12, 26, and 52 weeks among heavy smokers (at least 20 cigarettes daily). The study was 80% powered to detect a predetermined clinically relevant difference between the two treatment groups.
Study design: Randomized controlled trial (double-blinded)
Funding source: Industry plus government
Setting: Outpatient (any)
Reference: EbbertJOHatsukamiDKCroghanITet alCombination varenicline and bupropion SR for tobacco-dependence treatment in cigarette smokers: a randomized trial. JAMA.2014; 311( 2): 155– 163.