Combination therapy does not improve ability to quit smoking after one year

Among cigarette smokers, the combined use of the smoking cessation medications varenicline and bupropion, compared with varenicline alone, resulted in better rates of smoking abstinence at 12 weeks, but rates were similar after one year, according to a study in the January 8 issue of JAMA.

Smoking accounts for 62 percent of deaths among female smokers and 60 percent of deaths among male smokers. Innovative pharmacotherapeutic approaches to tobacco-dependence treatment need investigation to reduce smoking-related death and disability, according to background information in the article. "Exploration of combination therapy with existing drugs may provide the best opportunity to advance treatment in the absence of any new pharmacotherapies for tobacco dependence."

Jon O. Ebbert, M.D., M.Sc., of the Mayo Clinic, Rochester, Minn., and colleagues investigated the efficacy of combination pharmacotherapy with varenicline and bupropion SR (sustained-release) for smoking cessation, compared with varenicline alone (monotherapy). The trial included 315 adults who completed the study. Participants were randomized to 12 weeks of varenicline and bupropion SR or varenicline and placebo. There was follow-up through week 52.

The primary outcome was abstinence rates at week 12, defined as prolonged abstinence (no smoking from 2 weeks after the target quit date) and 7-day point-prevalence abstinence (no smoking past 7 days). Outcomes were biochemically confirmed.

Combination therapy was associated with significantly higher prolonged smoking abstinence rates at 12 (53.0 percent vs. 43.2 percent) and 26 weeks (36.6 percent vs. 27.6 percent) compared with varenicline alone. No significant differences were observed in prolonged smoking abstinence rates between the 2 groups at 52 weeks (30.9 percent vs. 24.5 percent).

No significant differences were observed between the 2 groups at any time point for 7-day point-prevalence smoking abstinence rates.

Anxiety was reported more commonly with combination therapy than with varenicline monotherapy (7.2 percent vs. 3.1 percent), as were depressive symptoms (3.6 percent vs. 0.8 percent).

"Among cigarette smokers, combined use of varenicline and bupropion, compared with varenicline alone, resulted in an increase in prolonged abstinence but not 7-day point-prevalence at 12 and 26 weeks; neither outcome was significantly different at 52 weeks. Further research is required to determine the role of combination treatment in smoking cessation," the authors conclude.