Chantix, manufactured by Pfizer, is a smoking cessation drug that has been linked to serious side effects, such as depression, violent mood swings, suicidal thoughts, and seizures. Chantix was originally approved for sale in the United States in May 2006, but the FDA recently announced that it will require a boxed warning label to be placed on Chantix packaging advising physicians of an increased risk of suicide in patients taking the drug. Family and friends who witness any of the above behaviors in people taking Chantix should advise the person to stop taking the drug and consult a physician immediately.