Impact of symptoms experienced by varenicline users on tobacco treatment in a real world setting.

This article examines reported symptoms, nonsmoking rates, and medication use among 1,018 smokers using varenicline in a randomized trial comparing three forms of behavioral support for smoking cessation (phone, Web, or phone + Web). One month after beginning varenicline, 168 people (17%) had discontinued the medication. Most (53%) quit due to side effects and other symptoms. The most common side effect among all users was nausea (reported by 57% of users). At 1 month post medication initiation, those not taking varenicline were more likely to report smoking than those who continued the medication (57% vs. 16%, p < .001). Women reported more symptoms but did not discontinue medication at higher rates. Participants who received any telephone counseling (n = 681) were less likely to discontinue their medication than those with Web support only (15% vs. 21%, p < .01). Counseling may improve tolerance of this medication and reduce the rate of discontinuation due to side effects.