Safety and Effectiveness of Varenicline in a Veteran Population with a High Prevalence of Mental Illness

Abstract

Background Varenicline is a selective nicotinic receptor partial agonist used to aid in the process of smoking cessation. Research on varenicline's approval for marketing demonstrated that after 12 weeks of treatment, at least 44% of patients successfully quit smoking and, on average, 13% of individuals discontinued therapy due to an adverse drug event (ADE). Growing postmarketing data linked varenicline to an increase in neuropsychiatric symptoms. Objective To evaluate the safety profile, specifically psychiatric symptoms, and effectiveness of varenicline in a veteran population and to determine whether there is an association among specific baseline demographics and success rate. Methods The study was a retrospective review of a prospective performance measure involving veterans initiated on varenicline. Patients were contacted via telephone throughout treatment and at week 12 for effectiveness follow-up. Smoking history was obtained and medication counseling was provided. The primary endpoint was tobacco cessation between weeks 9 and 12 of therapy. Varenicline's safety profile and discontinuation rates due to ADEs were also analyzed. Results Of the 50 patients included in the study, 30% (n = 15) successfully quit smoking and 70% (n = 35) failed therapy (lack of effectiveness, n = 22; intolerability, n = 13). Prevalence of underlying mental illness in the success group (4/15; 27%) versus failure group (20/35; 57%) was statistically significant (p< 0.001). All patients who discontinued therapy due to an increase in mood and behavioral changes (n = 4) had an underlying psychiatric illness. The study results demonstrate a lower success rate and a higher incidence of discontinuation due to an ADE in our veteran population compared with premarketing data. An inverse association was shown between psychiatric disorders and success. Conclusions Cautious treatment initiation and close monitoring of veterans initiated on varenicline are warranted. Furthermore, the results from this study demonstrate the need for prospective effectiveness trials to determine the clinical significance of the results.