thinking or mood, hostility, agitation, depressed mood and suicidal thoughts or actions while taking or after stopping chantix. if you notice any of these stop taking chantix and call your doctor right away. tell your doctor about any history of depression or other mental health problems, which could get worse while taking chantix. don't take chantix if you've had a serious allergic or skin reaction to it. if you develop these stop taking chantix and see your doctor right away as some can be life-threatening. tell your doctor if you have a history of heart or blood vessel problems, or if you develop new or worse symptoms. get medical help right away if you have symptoms of a heart attack or stroke. use caution when driving or operating machinery. common side effects include nausea, trouble sleeping and unusual dreams. people around you...they say, you're much bigger than this. and you are. [ male announcer ] ask your doctor if chantix is right for you.