Tolerability profile of varenicline in current medical practice

INTRODUCTION: Varenicline (Champix) was approved in France in 2006 as an aid to smoking cessation treatment. Although there is a consensus on its efficacy, its tolerability is debatable. This article sought to clarify its tolerability profile in current medical practice. MATERIALS AND METHODS: This retrospective study examined tolerance of varenicline prescribed to smokers who wanted to quit smoking in 10 "Stop-Smoking" consultation centers around France. It included all patients who used varenicline during the one-year (February 12, 2007, to February 12, 2008) study period. RESULTS: At least one adverse event (AE) was reported by 45.9% of the 338 patients, with a total of 343. AE incidence was higher among women (51.5%) than men (40.5%) (OR=1.56, 95% CI: 0.99-2.47, p=0.026). There were 32 unexpected AEs, that is, not listed in the initial new drug application, reported by 23 patients, including 19 psychiatric AEs. Of the 8 serious AEs, 3 were of neurological origin. CONCLUSION: This retrospective study confirmed the tolerability issues for varenicline, identified during the phase II-phase III development program and confirmed afterwards. It raises the following questions: Should varenicline be prescribed as a second-line therapy? Is there a patient type for which varenicline would be more - or less - appropriate? Can the tolerability profile be improved by reducing dosage while maintaining the level of efficacy or by co-administering symptomatic treatment more systematically? These are questions that new studies evaluating varenicline tolerability should answer.