Good adherence, defined by convention as taking 80% or greater of the prescribed regimen (DiMatteo, http://www.selleckchem.com/products/Cisplatin.html Giordani, Lepper, & Croghan, 2002), was strongly associated with smoking cessation. More than half (52.2%) of those who reported good adherence were abstinent at 6-month follow-up, whereas only a quarter (25.4%) of those who reported taking varenicline for less than 80% of the days prescribed were abstinent at 6 months (��(1)2 = 73.1, p < .0001). Reasons for Stopping Varenicline Smokers were significantly more likely than nonsmokers to report having stopped taking varenicline at 21-day and 12-week follow-ups (see Table 3). Overall, the most frequently endorsed reasons for stopping varenicline early were side effects and perceived lack of need. The reasons for stopping varenicline given by smokers and nonsmokers are shown in Table 3.

More than half of smokers (53%) and nonsmokers (52.8%) who were no longer taking varenicline at 21-day follow-up indicated they stopped due to side effects. By the 12-week follow-up, a significantly greater proportion of smokers (45.4%) than nonsmokers (29.2%) who were no longer taking varenicline reported side effects as a reason for stopping. A high proportion of nonsmokers who stopped varenicline indicated they felt it was not needed (27.8% at 21 days and 43.3% at 12 weeks), whereas few smokers indicated they stopped varenicline due to not needing it (13.7% at 21 days and 11.9% at 12 weeks). Relatively few participants no longer taking varenicline indicated they stopped due to feeling it was not working.

However, the proportion of smokers who indicated they stopped varenicline due to the medication not working was higher (11.9%) than that of nonsmokers who endorsed this reason for stopping (3.2%). Predictors of Varenicline Adherence Univariate linear regression analyses were conducted to identify predictors of varenicline adherence as measured by the reported number of days varenicline was taken during the 6-month study period and by the purposeful nonadherence scale of the MAQ at 12 weeks post target quit date. Older age, greater baseline self-efficacy for adhering to varenicline, and less initial nicotine withdrawal symptom severity (at 21-day follow-up) were found to significantly predict both greater number of days varenicline was taken and less purposeful nonadherence (see Table 4).

Gender and education were not significantly Carfilzomib associated with varenicline days taken but were significant predictors of less purposeful nonadherence. Baseline measures of depression, treatment outcome expectations, presence of smokers in the home, and nicotine dependence were not significant predictors of varenicline days taken; these baseline factors were similarly unrelated to purposeful nonadherence, with the exception of cigarettes per day.