Two drugs used to help people stop smoking varenicline (Chantix) and bupropion (Zyban) carry a significantly increased risk of depression and suicidal or self-injurious behavior, according to a new study published in the Public Library of Science.
Researchers from the Institute for Safe Medication Practices in Alexandria, Virginia, analyzed adverse event reports among smokers who had been prescribed one of these drugs to help them quit. They discovered that those taking varenicline had a significantly increased risk of serious psychiatric side effects compared to patients using nicotine replacement therapy. The same was true for bupropion an antidepressant sold as Zyban for smokers although to a much lesser extent. Out of the more than 3,000 reported cases of suicidal/self-injurious behavior or depression analyzed in the study, 90 percent were associated with varenicline, 7 percent with bupropion, and only 3 percent with nicotine replacement. Furthermore, varenicline had a thirty-fold higher risk of such effects when compared to a control group. Considering that varenicline works by blocking the effect of nicotine on the brain, ACSH s Dr. Ruth Kava says that the results make sense. Many people self-medicate with nicotine for depression, she explains. So blocking those nicotine receptors might thus be expected to increase a person s depression.
The researchers took the FDA to task for an announcement the agency had made, which downplayed the drug s risks. Although in 2009 the FDA slapped the drug with a black-box warning about potential side effects that include mood changes or suicidal thoughts, the agency s recent statement claimed that the data showed no particular risk of psychiatric side effects from using varenicline. Yet this statement considered only those few events of depression and suicidal or self-injurious behavior that were serious enough to land the patient in the hospital thus excluding a large number of less severe cases and underestimating the real risks of varenicline, and, to a lesser extent, bupropion.
Based on the results, the researchers conclude that the risks associated with varenicline render it unsuitable for first-line use in smoking cessation. ACSH staffers agree with this conclusion, given the troubling risks associated with the use of these drugs. In light of this study, ACSH s Dr. Elizabeth Whelan questions why public health officials continue to support the use of either drug. Rather than promoting drugs with such a poor risk-benefit profile, she says, public health authorities, both governmental and nonprofit, should counsel smokers about harm reduction options like smokeless tobacco, which do not pose such a risk."