Last week, the FDA reported that two federally funded clinical trials, together studying more than 26,000 patients, showed that Chantix did not increase depression and suicidal thoughts compared with other stop-smoking treatments. However, regulators noted that these reports came only from hospitalizations, which do not always happen when patients experience depression or suicidal thoughts.
"We continue to believe that when used as directed in the currently approved labeling, Chantix is a safe and effective treatment to help patients stop smoking," an FDA spokeswoman said in a statement.
The FDA approved Chantix in 2006, and since then, nearly 22 million prescriptions have been written and almost 9 million people got the drug from retail pharmacies. Studies showed that 33 percent of smokers who took Chantix were able to avoid tobacco six months after quitting, compared with 14 percent who took a placebo.
In 2008, the U.S. Federal Aviation Administration banned commercial pilots from using Chantix after reports surfaced that the drug was linked to black-outs and vision problems. Truck drivers have also been restricted from using Chantix.
The U.S. Veterans Administration (VA) recommends that patients take Chantix only after trying to quit smoking using nicotine replacement drugs and Zyban, and even then, the VA suggests that patients' mental health should be evaluated before taking the drug.
Furberg and his colleagues think the FDA should adopt the VA's approach to Chantix and should update the drug's "black box" warning to indicate that it is riskier than Zyban and other treatments. Furberg said the benefits of stopping smoking don't outweigh the risks of the psychological symptoms connected to Chantix.
"Smoking is bad and if we have an effective treatment for smoking cessation, I would promote it," Furberg said. "But the benefit of this drug is so weak that you can't tolerate the bad effects that come with it."