Evaluating the Real-World Effectiveness of Bupropion Versus Varenicline for Smoking Cessation: Exploring the Role of Nicotine Metabolism and Medication Adherenc

Bupropion and varenicline are effective, first-line prescription-only pharmacotherapies for smoking cessation; however, their real-world use is limited by affordability and accessibility. Using a novel internet-based randomized design, we evaluated the real-world effectiveness of mailed bupropion and varenicline, as well as the roles of nicotine metabolism (NMR) and medication adherence, in a sample of interested smokers using web-based recruitment and follow up. Quit rates at end of treatment (EOT) were significantly higher for varenicline (30.2%) compared to bupropion (19.6%). Quit rates at 6 months (14.0%) and 12 months (12.1%) were not significantly different between bupropion and varenicline. Increased medication compliance significantly improved cessation outcomes at EOT. NMR was associated with nicotine dependence. Varenicline benefited Slow Metabolizers of nicotine whilst bupropion benefited Normal Metabolizers. Even though real-world quit rates were comparable to clinical trials, improving medication compliance and implementing personalized pharmacological and behavioral interventions are promising approaches to increase efficacy of smoking cessation pharmacotherapies.