Smoking cessation rates no higher when bupropion added to varenicline treatment

Combined treatment with varenicline and bupropion sustained-release (SR) was negligibly more effective than varenicline alone in helping smokers quit, a recent study found.

The controlled trial randomized 506 adult smokers in the Midwestern U.S. to 12 weeks of varenicline and bupropion SR or varenicline and placebo. The study was conducted between October 2009 and April 2013; outcomes were biochemically confirmed prolonged abstinence (no smoking since 2 weeks after quit date) and abstinence for the past 7 days, measured at week 12, week 26 and week 52. Results were published in the Jan. 8 Journal of the American Medical Association, a tobacco-themed issue.

Only 315 patients (62% of the initial group) completed the 12 weeks of therapy. Of those who finished, the combination group had slightly higher rates of prolonged abstinence at 12 weeks (53.0% vs. 43.2% on varenicline alone; odds ratio [OR], 1.49; 95% CI, 1.05 to 2.12; P=0.03), but there was no significant difference in 7-day abstinence (56.2% vs. 48.6%; P=0.09). The results were similar at 26 weeks: Prolonged abstinence was 36.6% on combination therapy and 27.6% on varenicline (OR, 1.52; 95% CI, 1.04 to 2.22; P=0.03), but no significant difference was found in smoking over the previous 7 days (38.2% vs. 31.9%; P=0.14). At 52-week follow up, the groups showed no significant difference on either measure, with about a quarter of patients having successfully quit.

The groups did differ in some adverse events. Patients on combination therapy reported more anxiety (7.2% vs. 3.1%; P=0.04) and depressive symptoms (3.6% vs. 0.8%; P=0.03). Researchers noted that use of bupropion SR for tobacco dependence has previously been found to increase anxiety. The patients on combination treatment who successfully quit had less weight gain at week 12 than those on monotherapy, the authors noted. This suggests that combination therapy could be a good option for patients whose concern about weight gain could impede their smoking cessation.

The authors noted several limitations to the study, including the high dropout rate, which could have led to over- or underestimation of the treatment effects. Patients with serious medical or psychiatric illnesses were also excluded from the study, so the results may not be generalizable to all smokers. The study authors concluded by calling for more research on the role of combination treatment in smoking cessation.