The Food and Drug Administration (FDA) warns that patients taking the popular stop-smoking drugs Chantix and Zyban should be watched closely for signs of serious mental illness. The warning was issued following mounting reports of bizarre behavior, including suicide, among users of the drugs. Pfizer is the maker of Chantix (varenicline), and GlaxoSmithKine is the manufacturer of Zyban (buproprion). Buproprion is also sold under the brand name Wellbutrin, as a treatment for depression. Both of the drugs will now be required to carry “black box” labels warning that people who take the drugs should be closely monitored for signs of suicidal thoughts, depression, hostility, and other behavioral changes. In addition, both drug companies will be required to conduct clinical trials for the purpose of assessing the mental health risks associated with the uses of the drugs. Unlike the clinical trials leading to the FDA approval of the drugs, the new trials will enroll smokers with underlying psychiatric disorders. Pfizer has already begun enrollment of schizophrenia patients in a trial. Since the drugs have been marketed, a total of 98 suicides and 188 attempted suicides have been seen in user of Chantix as well as 14 suicides and 17 attempted suicides in Zyban users, according to data from the FDA’s adverse event reporting system. However, officials stressed that fear of experiencing adverse symptoms should not stop patients from taking the smoking-cessation medications. According to Dr. Curtis J. Rosebraugh, director of a drug evaluation office at the FDA, “We don’t want to scare people off from trying a medication that could help them achieve this goal. You should just be careful.” He also added, “Stopping smoking is a goal we should all be working towards.” First marketed in 2006, Chantix has cornered about 90 percent of the prescription smoking-cessation drugs market, according to IMS Health, a health care information company. However, Chantix sales have fallen short of Pfizer’s expectations due to previous warnings of the drug’s side effects. Analysts do not foresee the FDA action having much effect on future sales because of the previous indications of psychiatric risks linked to use of Chantix. Dr. Steve Romano, Pfizer vice president and head of medical affairs, pointed out that since nicotine withdrawal can be very difficult for people to endure, and those who are trying to quit smoking are statistically inclined to be depressed and suicidal, it is difficult to identify the specific impact of the drugs on the risks. Regarding the black-box warning, he said, said, "The purpose of the new boxed warning is to raise particular issue of concern to physicians so they can mitigate it, by being more vigilant and monitor patients more actively.” It is not clear why the drugs are associated with mental problems. Although some patients may be experiencing nicotine withdrawal, some adverse affects involved patients who had yet to stop smoking. Curt Rosebraugh, MD, MPH, director of one of the FDA's drug evaluation units, said that some of the suicide reports came from Chantix users who were still smoking. Officials have also acknowledged that many of the events happened soon after patients either began or stopped therapy. However, regarding the odd behaviors, FDA official Dr. Robert Temple said, “If this is nicotine withdrawal, it really doesn’t matter. You need to pay attention to them.”