Users should be aware of the possible emergence of serious neuropsychiatric symptoms (examples include depression and suicidal ideation) when attempting to quit smoking with or without varenicline.

Some of these may be a symptoms of nicotine withdrawal, and may occur more frequently in people with a history of psychiatric disorders.

If serious neuropsychiatric symptoms occur, varenicline should be discontinued immediately and a healthcare professional should be contacted.

Similarly, users should also seek medical attention immediately if they experience signs and symptoms of myocardial infarction or stroke.

Seizures have been reported with use of varenicline, so it should be used cautiously in patients with a history of seizures.

Varenicline is contraindicated in those showing previous hypersensitivity reactions.

Vareniciline should also be avoided in pregnancy.