Singh et al. pooled the data from 14 previous studies, including 8,200 patients in total. Though the Rigotti study, which looked at those with cardiovascular disease, was included in their meta-analysis, the vast majority of patients included in their research did not have cardiovascular disease.
Despite the relatively heart-healthy makeup of their study population, an increased risk in heart attack, stroke and other serious heart complications was still associated among those taking the drug. The effect was so strong that many experts in cardiology and smoking cessation feel heightened caution and limited, if not discontinued, use of Chantix is justified.
"The data … justify a black box warning on Chantix labeling about the cardiovascular risk," says Dr. Jay Cohn, director of the Rasmussen Center for Cardiovascular Disease Prevention at the University of Minnesota Medical School.
"It may be justified to accept the small increase in absolute risk [of adverse cardiac events], to gain the long-term benefit of smoking cessation … in certain individuals," she says.
For some clinicians, the psychological risks combined with the potential cardiovascular risks are enough to stay away from Chantix altogether. Spangler hasn't prescribed it in years and Daniel Seidman, director of the Smoking Cessation Services at Columbia University Medical Center, says he has "avoided Chantix in my clinical work with smokers precisely because of safety concerns. This [study] is yet another black eye for Chantix."
Combining nicotine replacement, such as the gum and the patch or lozenge, has been shown to be more effective for quitting anyway, he adds.
Singh takes it a step further, calling for the FDA to withdraw Chantix from the market altogether. Most importantly, however, he wants patients and doctors to be aware of all the risks that may go along with using the drug.
"These results are very concerning. Unfortunately, this was concerning five years ago. We can't wait another five years to tell smokers that they might be at risk for heart problems when on Chantix," says Singh.
Sales of Chantix totaled $755 million last year. Thirteen million people worldwide have been prescribed Chantix.