The FDA ( Food and Drug Administration ) has reviewed the results from two FDA-sponsored epidemiological studies that evaluated the risk of neuropsychiatric adverse events associated with the smoking cessation drug Varenicline ( Chantix; in Europe: Champix ).
Neither study found a difference in risk of neuropsychiatric hospitalizations between Varenicline and nicotine replacement therapy ( NRT; e.g., NicoDerm patches ).
However, 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.
Healthcare professionals and patients should continue to follow the recommendations in the physician label and the patient Medication Guide, and to monitor for neuropsychiatric symptoms when prescribing or using Varenicline.
The drug manufacturer, Pfizer, is conducting a large safety clinical trial of Varenicline to assess neuropsychiatric adverse events, and results from this study are expected in 2017.
In 2008, FDA informed healthcare professionals and patients that it appears increasingly likely that there is an association between Varenicline and serious neuropsychiatric symptoms.
If patients, their families, or caregivers notice agitation, depressed mood, or changes in behavior that are not typical for the patient or if the patient has suicidal thoughts or actions, the patient should stop taking Varenicline and contact their healthcare professional.
In 2007, FDA informed healthcare professionals of reports of suicidal thoughts and aggressive and erratic behavior in patient who have taken Varenicline, a smoking cessation drug. There are also reports of patients experiencing drowsiness that affected their ability to drive or operate machinery.
A preliminary assessment revealed that many of the cases reflect new-onset of depressed mood, suicidal ideation, and changes in emotion and behavior within days to weeks of initiating Varenicline treatment. The role of Varenicline in these cases is not clear because smoking cessation, with or without treatment, is associated with nicotine withdrawal symptoms and has also been associated with the exacerbation of underlying psychiatric illness.
However, not all patients described in the cases had preexisting psychiatric illness and not all had discontinued smoking.
Healthcare professionals should monitor patients taking Varenicline for behavior and mood changes. Patients taking this product should report behavior or mood changes to their doctor and use caution when driving or operating machinery until they know how quitting smoking with Varenicline may affect them.
Source: FDA, 2011