Chantix Users At No Additional Psychiatric Risk: Studies
October 25, 2011

Chantix Users At No Additional Psychiatric Risk: Studies

Smokers who take the anti-smoking drug Chantix are not at higher risk of being hospitalized for psychiatric events such as depression, compared with smokers who use nicotine patches, the U.S. Food and Drug Administration (FDA) said on Monday.

The agency based its findings on a review of two recent studies that compared Pfizer´s Chantix to standard nicotine replacement therapy such as the Nicoderm nicotine patch from GlaxoSmithKline.

Previous reports had linked Pfizer's non-nicotine pill with depression and suicidal thoughts, and clinical trials had shown the pill linked to nightmares. 

The FDA has been investigating these reports since 2007, and has previously said that Chantix users with a history of mental illness had seen their symptoms worsen, while those without a history of mental illness had experienced psychiatric symptoms.

However, the agency walked back that position on Monday, saying that two federally-funded studies involving more than 26,000 patients did not show an increased rate of psychiatric hospitalizations among Chantix patients, compared with those using nicotine patches and other smoking cessation treatments.

“Neither study found a difference in risk of neuropsychiatric hospitalizations between Chantix and nicotine replacement therapy (NRT; e.g., NicoDerm patches),” the agency said, referring to studies conducted by the Department of Veterans Affairs and the Department of Defense.

However, FDA regulators emphasized that the studies only looked at psychiatric problems that resulted in hospitalization, meaning many issues likely went unreported.

“Both studies had a number of study design limitations, including only assessing neuropsychiatric events that resulted in hospitalization, and not having a large enough sample size to detect rare adverse events,” the agency said.

“Although these two studies did not suggest an increased risk of neuropsychiatric events that result in hospitalization, they do not rule out an increased risk of other neuropsychiatric events with Chantix.”

The FDA said it is continuing to investigate the matter, and recommends patients consult their doctors if they experience side effects with the drug.

"Healthcare professionals should advise patients and caregivers that the patient should immediately stop taking Chantix and contact a healthcare professional if agitation, hostility, depressed mood, or changes in behavior or thinking that are not typical for the patient are observed," the FDA said in an online statement.

Chantix works by binding to the same places in the brain that nicotine does, thereby blocking the nicotine while still causing a release of the "feel-good" chemical dopamine. 

The drug's label currently carries the most serious type of warning, and lists hostility, agitation, depression and suicidal thoughts and behavior among its possible side effects.

Nearly 9 million Americans have filled prescriptions for Chantix since it received FDA approval in May 2006. However, some groups, such as the Federal Aviation Administration, have banned the drug for some employees out of concern it could interfere with their work.

New York-based Pfizer reported $755 million in Chantix sales last year, a drop of 14 percent since its peak sales of $883 million in 2007.

The company said it is conducting its own large-scale study of the behavioral effects of Chantix, although results won't be available until 2017.

"We are reviewing this important information for smokers provided by the FDA,” Pfizer said.


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