Risks of using Chantix to stop smoking include seizures, increased hostility, suicidal thoughts and depression, as reported by the U.S. Food and Drug Administration. Other side effects include nausea, constipation, vomiting, gas and sleep problems. Clinical trials show that taking Chantix significantly increases the likelihood of quitting smoking compared to treatment with a placebo.
Adverse effects of taking Chantix include skin reactions and new or worsening heart and blood vessel problems in people with pre-existing cardiovascular problems, according to the U.S. Food and Drug Administration. The drug may also change how people react to alcohol.
Patients should stop taking Chantix and call their health care provider immediately if they experience paranoia, confusion, hallucinations, abnormal sensations, mania and anxiety, advises Chantix. Symptoms of an allergic reaction requiring emergency medical assistance include rashes and swelling of the mouth, face and throat.
Chantix is very effective in helping a person quit smoking, according to WebMD. It works by blocking nicotine receptors in the brain, taking away the rewarding effect of smoking. The drug also mimics, to a lesser extent, the effects of nicotine on the brain. The U.S. Food and Drug Administration has evaluated Chantix and concluded that its benefits outweigh the risks.