Key Ingredient in Chantix Does Not Appear to Cause Psychiatric Events, Study Finds

As Pfizer Pharmaceuticals pays out millions of dollars in claims related to depression and suicide associated with the antismoking drug Chantix, the study "Varenicline, Smoking Cessation, and Neuropsychiatric Adverse Events" reported today in AJP in Advance, finds that the drug may be less harmful than other smoking-cessation therapies. Researchers from the Department of Psychiatry at the University of Chicago and at Columbia University analyzed data from previous placebo-controlled and drug-comparison trials to assess the efficacy and safety of varenicline—the key in ingredient in Chantix—in more than 40,000 users with and without psychiatric disorders. 

The data showed that varenicline was highly associated with inducing nausea among patients, but not suicide events, depression, or aggression. Current or past psychiatric illness increased the risk of neuropsychiatric events equally among the varenicline and placebo groups. In the drug-comparison studies, the rate of neuropsychiatric events in the varenicline cohort was significantly less than in those receiving nicotine-replacement therapy. Overall, varenicline was more successful in achieving smoking abstinence than placebo or nicotine-replacement therapy.

J. John Mann, M.D., study author and vice chair for research in the Department of Psychiatry at Columbia, told Psychiatric News that, “Patients report side effects. Often they are real and important.... Sometimes the side effects or adverse effects reported are due a change in the illness or in this case due to nicotine withdrawal or the loss of the cognitive enhancing effects of nicotine…. Some reports are due to the patient being alert to the possibility [of a side effect] and [thus] more likely to report its occurrence, and sometimes the person feels they have the complication but objective examination fails to confirm this.”

The study was funded by the National Institute of Mental Health. Pfizer provided no financial support.

For information on research into varenicline, see the Psychiatric News article "Varenicline Shows Promise as Alcohol Abuse Treatment." For a report on nicotine-vaccine research, see the article "Nicotine Vaccine's Effect on Brain Evaluated."

(Image: Fabio Berti/shutterstock.com)