Varenicline. Sold under the trade name Chantix in the U.S. and Champix in the U.K. and Commonwealth countries. It's a smoking cessation medication, one of the known side effects of which is suicidal ideation.
Some people have had new or worse mental health problems, such as changes in behavior or thinking, aggression, hostility, agitation, depressed mood, or suicidal thoughts or actions while taking or after stopping CHANTIX. These symptoms happened more often in people who had a history of mental health problems. Stop taking CHANTIX and call your healthcare provider right away if you, your family, or caregiver notice any of these symptoms. Before starting CHANTIX, tell your healthcare provider if you ever had depression or other mental health problems.