Varenicline (marketed as Chantix) was approved by the U.S. Food and Drug Administration (FDA) as an aid to smoking cessation treatment in May 2006. A public health advisory was issued and black box warning was added to the prescribing information for varenicline in July 2009 because of the potential for serious psychiatric side effects including suicidal thoughts and actions.
While the potential psychiatric side effects associated with varenicline are of greatest concern, other uncommon but potentially deadly side effects are associated with use of this medication.
Suicidal Thoughts and Actions
The FDA-approved black box label for varenicline specifically warns that, "Serious neuropsychiatric events, including, but not limited to depression, suicidal ideation, suicide attempt and completed suicide have been reported in patients taking Chantix." An FDA review of adverse events reported during the first 18 months after approval of varenicline found 116 cases of suicidal thoughts and 37 cases of suicidal behavior. Nineteen of the 37 cases of suicidal behaviors resulted in death. Notably, while 50 percent of people experiencing suicidal thoughts or behaviors had a prior psychiatric history, 86 percent reported their suicidal symptoms began while taking the drug.
Aggressive Behavior
In addition to the association with suicidal thoughts and behaviors, varenicline has been linked to aggressive behavior. The Institute for Safe Medicine Practices stated in its May 7, 2009 newsletter "QuarterWatch" that from the time of drug approval in May 2006 through the third quarter of 2008, the FDA had received reports of 30 cases of physical assaults, 148 cases of homicidal thoughts, and 331 cases of aggression. The warnings listed in the prescribing information for varenicline specifically note post-marketing reports of psychosis, paranoia, delusions, homicidal ideation and hostility.
Angioedema and Allergic Reactions
Potentially life-threatening allergic reactions, including angioedema, have been reported in people taking varenicline. Angioedema is an allergic reaction characterized by sudden swelling of the face, mouth, throat and extremities. It can be life-threatening if the airways are affected by the swelling. Any allergic reaction associated with difficulty breathing is a medical emergency.
Stevens-Johnson Syndrome
Since the FDA approved varenicline in 2006, cases of Stevens-Johnson syndrome have been reported in people taking the drug. Stevens-Johnson syndrome (SJS) is a severe blistering reaction of the skin and mucosal surfaces--the linings of the cavities of the body that have communication with the outside environment such as the mouth, throat and airways. The extensive blistering of SJS causes the upper layer of the skin (the epidermis) to detach and die. Up to 10 percent of the total body surface area may be affected by this epidermal detachment. SJS is potentially life-threatening because of extensive loss of fluid through the open skin, and the high risk of serious infection.
Accidental Injuries
In a March 11, 2009 news article, "Studies Linking Smoking-Cessation Drug with Suicide Risk Sparks Concerns" in "The Journal of the American Medical Association," staff writer Bridget M. Kuehn noted that 2,899 reports of serious injury linked to varenicline had been received by the FDA from the last quarter of 2007 through the second quarter of 2008. Although most of these reports involved psychiatric problems, Kuehn specified that motor vehicle crashes were also frequently reported. Kuehn further stated that concerns about possible impairment of individuals' cognitive or motor abilities, "... have spurred the Federal Aviation Administration, the Department of Defense, and the Department of Transportation to ban use of the drugs by individuals such as pilots and truck drivers."
References
- U.S. Food and Drug Administration: Approval package for varenicline
- U.S. Food and Drug Administration: Public health advisory, FDA requires new boxed warnings for the smoking cessation drugs Chantix and Zyban
- U.S. Food and Drug Administration: Information for healthcare professionals, varenicline
- U.S. Food and Drug Administration: Chantix prescribing information
- U.S. Food and Drug Administration: Drug safety newsletter
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