FDA lifts Boxed Warning on Chantix and Zyban

Based on a US Food and Drug Administration review of a large clinical trial that FDA required the drug companies to conduct, the agency has determined the risk of serious side effects on mood, behavior, or thinking with the stop-smoking medicines Pfizer’s (NYSE: PFE) Chantix (varenicline) and GlaxoSmithKline’s (LSE: GSK) Zyban (bupropion) is lower than previously suspected.

The risk of these mental health side effects is still present, especially in those currently being treated for mental illnesses such as depression, anxiety disorders, or schizophrenia, or who have been treated for mental illnesses in the past. However, most people who had these side effects did not have serious consequences such as hospitalization. The results of the trial confirm that the benefits of stopping smoking outweigh the risks of these medicines.

As a result of the large clinical trial review, FDA is removing the Boxed Warning, FDA’s sternest warning for an approved medicine, for serious mental health side effects from the Chantix drug label in 2009. The language describing the serious mental health side effects seen in patients quitting smoking will also be removed from the Boxed Warning in the Zyban label. The FDA is also updating the existing warning section in both labels that describes the side effects on mood, behavior, or thinking to include the results from the clinical trial. This decision is consistent with the recommendations of external experts at a September 2016 FDA Advisory Committee meeting. The patient Medication Guide that explains the risks associated with the use of the medicines will continue to be provided with every patient prescription; however, the risk evaluation and mitigation strategy (REMS) that formally required the Medication Guide will be removed.