The FDA is adding a boxed warning on the prescribing information for the smoking-cessation drugs varenicline (Chantix, Pfizer) and bupropion (Zyban drug, GlaxoSmithKline) to highlight the risk of serious mental health events, such as behavioral changes, depressed mood, hostility, and suicidal thoughts.
Some patients taking the drugs experienced unusual changes in behavior, became depressed, or had worsening depression and thoughts of suicide or dying. The problems often began shortly after they started taking the drug and ended when they stopped taking it; however, some patients continued to have symptoms after stopping the medication.
Neither agent contains nicotine, and some of the symptoms might be a response to nicotine withdrawal.
The FDA also is requesting more information in the warnings section of the prescribing information and an updated medication guide.
Source: FDA, July 1, 2009