chantix or history of seizures. don't take chantix if you've had a serious allergic or skin reaction to it. if you develop these stop 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 develop new or worse symptoms. get medical help right away if you have symptoms of a heart attack or stroke. decrease alcohol use while taking chantix. use caution when driving or operating machinery. common side effects include nausea trouble sleeping and unusual dreams. chantix absolutely helped me quit smoking. ask your doctor if chantix is right for you.