Safety and Effectiveness of Varenicline in Korean Smokers: A Nationwide Post-Marketing Surveillance Study

PURPOSE: Varenicline has demonstrated its safety and efficacy in Western studies including <3% of Asian participants. This prospective multi-center observational study investigated the safety and effectiveness of varenicline in Korean smokers. PATIENTS AND METHODS: Smokers prescribed varenicline for the first time were enrolled from 252 medical institutions. Investigators recorded and graded all adverse events (AEs). To assess the effectiveness of varenicline, the 7-day point prevalence (PP) of smoking cessation was evaluated at the four visits during the 12-week treatment course. Rates of AE incidence and smoking cessation were analyzed using Chi-squared test or Fisher’s exact test. This study is registered with ClinicalTrials.gov, number NCT00483002. RESULTS: A total of 3719 and 3700 study subjects were included in the safety and effectiveness analyses, respectively. Overall, 346 (9.3%) subjects experienced 471 AEs: 358 mild, 97 moderate, 9 severe, and 7 serious. The most frequent AEs were nausea (5.1%), dyspepsia (0.8%), abnormal dreams (0.8%), insomnia (0.8%), and headache (0.7%). Among the subjects with AEs, 73 subjects discontinued treatment, of which 68 were due to AE occurrence. The 7-day PP of smoking cessation at weeks 1–2, 3–6, 7–10, and ≥ week 11 were 51.7% (387/749), 59.6% (1740/2922), 73.3% (1114/1520), and 77.0% (1116/1449), respectively (p for trend = 0.023). Comorbidities and allergies were associated with a higher incidence of AEs and lower smoking cessation rate (p < 0.05). Younger subjects, infrequent alcohol drinkers, and lighter smokers showed a higher smoking cessation rate (p < 0.05). CONCLUSION: Varenicline in adult Korean smokers was well tolerated and effective as a smoking cessation aid in routine clinical practice.