Federal regulators have ordered new safety language about quitting smoking on the smoking cessation drugs Chantix (varenicline) and Zyban (buproprion). The two stop smoking meds are getting the toughest warning added to their labels, alerting doctors and patients to potentially severe mental health risks when using these drug to quit smoking , including behavioral changes, depression, hostility, suicide, and suicidal thoughts, as well as warnings about allergic and skin reactions.
The FDA has been reviewing Chantix safety since 2007, after hundreds of reports of erratic, aggressive and suicidal behavior when using it as part of a smoking cessation program. But as the agency notes, it's difficult to confirm these drugs are directly responsible, because nicotine withdrawal itself can be very difficult to endure. There's also the possibility that when Chantix is used to stop smoking it exacerbates symptoms of underlying mental illness rather than causing them--a problem that would have gone undetected in clinical trials because they excluded patients with a history of mental illness.
Hence the new trials FDA is requiring both Pfizer and GlaxoSmithKline, Zyban's maker, to undertake. Pfizer says it's currently conducting a safety study involving patients with schizophrenia and is in talks with the FDA regarding comparative studies. Glaxo will also be required to study Zyban's mental health effects on patients, including those with pre-existing mental problems.
"The risk of serious adverse events while taking these smoking cessation/stop smoking products must be weighed against the significant health benefits of quitting smoking," said Janet Woodcock, M.D., director, the FDA's Center for Drug Evaluation and Research. "Smoking is the leading cause of preventable disease, disability, and death in the United States and we know these products are effective aids in helping people break their addiction to nicotine.
Pfizer won't yet say how the warning might affect its financial forecast or its Chantix sales force, but promises an update July 22 on sales figures for its primary care unit, in tandem with its earnings report. Meanwhile, GSK hasn't released a statement at all, despite the fact that the warning goes onto two of its meds: Zyban is sold as an antidepressant under the brand name Wellbutrin, and that drug gets updated "boxed warning" language added to its current "boxed warning" of suicidal thoughts and behavior. Generic versions, too. But Glaxo doesn't make much off Zyban, while Chantix is one of Pfizer's top selling meds, bringing in $846 million last year.
These products may not be the best stop smoking aids as alternatives to smoking and nicotine addiction. It may be preferable to seek other tips on quitting smoking with less potential for severe adversities.