• The most common adverse effect is mild-to-moderate nausea, which usually occurs early in the treatment period.
• Other common adverse effects include headache, insomnia, abnormal dreams, increased appetite, somnolence, dizziness, vomiting, constipation, diarrhoea, abdominal distension and discomfort, dyspepsia, flatulence, dry mouth, and fatigue.
• Varenicline may cause dizziness and somnolence, and therefore may influence the ability to drive and use machines. Advise the person not to drive, operate complex machinery, or engage in other potentially hazardous activities until it is known whether varenicline affects their ability to perform these activities.
• There have been reports of depression and suicidal ideation associated with the use of varenicline. Prescribers are advised that:
• Patients should be told to stop treatment and contact their doctor immediately if they develop suicidal thoughts or behaviour.
• Varenicline should be stopped immediately if agitation, depressed mood, or changes in behaviour are observed that are of concern to the patient, family, or caregivers.
• The safety and efficacy of varenicline in people with serious psychiatric illness have not been established. Patients who have a history of psychiatric illness should be monitored closely while taking varenicline.

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