depressed mood, suicidal thoughts or actions, seizures, new or worse heart or blood vessel problems, sleepwalking, or life-threatening allergic and skin reactions. decrease alcohol use. use caution driving or operating machinery. tell your doctor if you've had mental health problems. the most common side effect is nausea. talk to your doctor about chantix. ♪ ♪ award winning interface. ♪ ♪