Observational study of safety and efficacy of varenicline for smoking cessation among Filipino smokers

Objective: Varenicline, an alpha 4 beta 2 receptor nicotinic receptor partial agonist, is known to be an effective aid for smoking cessation. To date, few observational studies of varenicline have been conducted. This prospective, non-interventional, post-marketing surveillance study (NCT00794365) was designed to monitor the efficacy and safety of varenicline for 12 weeks in Filipino smokers who were motivated to quit. Research design and methods: This study was conducted between July 2, 2008, and November 23, 2009, in 70 centers throughout the Philippines. Participants were adult smokers who were prescribed varenicline (0.5 mg orally once daily, days 1 to 3; 0.5 mg twice daily, days 4 to 7; 1 mg twice daily for the remainder of a 12-week treatment period) for the first time. Participants made five clinic visits (weeks 0, 1, 4, 8, and 12). Main outcome measures: Adverse events (AEs) were recorded at each clinic visit and up to 28 days after administration of the last study treatment. Seven-day point prevalence of smoking cessation was measured at weeks 4, 8, and 12. Results: A total of 330 participants were enrolled into the study, of whom 251 (76.1%) completed the study. At the end of week 12, 57.6% (95% confidence interval, 52.0, 63.0) of participants had been abstinent for the previous 7 days. The most frequently reported AEs were headache (5.5%), dizziness (3.9%), and nausea (3.6%). Ten participants (3.0%) permanently discontinued varenicline treatment due to AEs, and 13 (3.9%) reduced their varenicline dose or discontinued treatment temporarily due to AEs. There were no reports of any serious AEs, deaths, suicidal ideation, or behavior. Conclusions: The results of this study in adult Filipino smokers prescribed varenicline for the first time during routine clinical practice demonstrate that varenicline was well tolerated and efficacious as an aid for smoking cessation.