depressed mood and suicidal thoughts or actions while taking or after stopping chantix. if you tice any of these symptoms or behaviors, stop taking chantix and call your doctor rig 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 retion to it. if you develop serious allergic or skin reactions, stop taking chantix and see your doctor right away, as some of these can be life-threatening. dosing may be different if you have kidney problems. until you know how chantix affects you, use caution when driving or operating machinery. common side effects include nausea, trouble sleeping, and unusual dreams. ♪ it feels wonderful. i on't smoke. i don't smoke. [ male announcer ] talk to your doctor to find out if chantix is right for you. learn about the chantix challeng antix may not work for everyone. if you aren quit after 12 weeks, we'll refund your cost of trying it. learn more at chantix.com.