Common side effects (≥5% and twice the rate observed in placebo-treated patients) include:
Nausea (30%)
Sleep disturbance (insomnia 18%; abnormal dreams 13%)
Constipation (8%)
Flatulence (6%)
Vomiting (5%)

Note to instructor(s): Per the manufacturer’s prescribing information, nausea was the most common adverse event associated with varenicline treatment. Nausea was generally described as mild or moderate and often transient; however, for some subjects, it was persistent over several months. The incidence of nausea was dose-dependent. Initial dose titration was beneficial in reducing the occurrence of nausea. Approximately 3% of subjects receiving varenicline 1 mg bid discontinued treatment prematurely because of nausea. For patients with intolerable nausea, dose reduction should be considered.

Pfizer, Inc. (2006, May). Chantix Package Insert. New York, NY.

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