Want to stop smoking but having a hard time kicking the habit? Consider adding Chantix to your quit kit. According to the Food and Drug Administration (FDA), Chantix imitates nicotine’s effect on the brain, which lessens withdrawal symptoms. The drug also limits the satisfaction you’ll experience if you backslide and resume smoking. In clinical trials among smokers who had averaged 21 cigarettes per day for about 25 years, 22% quit for at least a year. People taking Chantix were 14% more successful in quitting than people using Zyban, another smoking cessation drug. Available by prescription, Chantix’s side effects may include nausea, headache, gas and insomnia.