Chantix is regarded as one of the most effective ways to quit smoking for adults ages 18 and over. Clinical trials have found that about 22% of participants taking Chantix abstain from smoking after one year. A 2006 report from the Journal of the American Medical Association (JAMA) concluded that the drug quadruples a smoker’s likelihood of quitting. Be sure to check with your doctor before beginning any prescription drug treatment to quit smoking, especially if you have a medical condition, such as diabetes or pregnancy.