Time Frame

• Physicians typically prescribe Chantix for 12 weeks, with an additional 12-week prescription if the client has remained smoke-free and feels the need for longer-term assistance. Pfizer Inc. has told ABC News that the drug is safe to take for an entire year, while emphasizing that 24 weeks is the maximum time recommended on the labeling. Serious side effects reported are generally more common and more severe with long-term use.
  
  

Nausea During Use

• In clinical studies, the most frequent negative effect caused by Chantix use was mild or moderate nausea, occurring in up to 30 percent of users. In some people, nausea lasted through the entire three months of treatment. Up to 19 percent of people in the trials also experienced headaches or insomnia, again, some having these problems for the entire length of the study.
  
  

Mental Disorders

• Chantix may trigger the onset of psychiatric illnesses, including schizophrenia and bipolar disorder. It also may cause recurrence of these disorders, even if they were previously under control. Other negative mental side effects linked to Chantix include unusually aggressive behavior, agitation, depression, hallucinations, nightmares, and suicidal thoughts and attempts. In November 2007, the U.S. Food and Drug Administration said it had received 39 reports of suicide deaths associated with Chantix, and almost 500 reports of suicidal thoughts and behavior.
  
  

Physical Effects

• Chantix use has been linked to loss of consciousness, which may be related to abnormal heart rhythms that also might be caused by the drug. Chantix use may also cause seizures. Because some of these incidents resulted in traffic accidents, the Federal Aviation Administration in 2008 began prohibiting all of its pilots and air traffic controllers from using Chantix. Other adverse effects associated with Chantix include the onset of diabetes or pre-diabetes with no previous history of blood sugar issues, and permanently impaired vision, resulting in the need for corrective lenses.
  
  

Expert Insight

• The Institute for Safe Medication Practices (ISMP) found that Chantix accounted for more reports of serious negative drug events in the U.S. during the last quarter of 2007 than any other prescription medication. In its 3rd-quarter 2008 report, ISMP said Chantix continued to be responsible for more reports of serious negative psychiatric symptoms than any other prescription medication. Only three other prescription drugs ranked higher for causing serious injuries. Between May 2006 and December 2007, the FDA received over 170 reports of serious accidents associated with Chantix use, including 28 traffic incidents and 77 falls.