Last month, the Food and Drug Administration warned of newly discovered cardiovascular risks associated with Pfizer’s popular smoking-cessation drug Chantix. But it turns out those risks, which include higher occurrence of heart attack and other adverse cardiovascular events in Chantix users with heart disease, pale in comparison to the findings of a larger study that found many of the same risks exist in Chantix patients with no heart disease.
The new study, published in the Canadian Medical Association Journal, included the results of 14 random, blinded clinical trials that monitored cardiovascular health in more than 8,000 patients taking either Chantix or a placebo. Collectively, the trials found that 52 smokers in the Chantix groups suffered a heart attack, stroke, or other serious cardiovascular event while just 27 smokers taking placebo experienced the same cardiovascular problems. According to the New York Times, the “weighted, relative difference” between the two groups was 72 percent.
In the real world, the findings of these two latest Chantix studies mean that “doctors could expect to get one extra cardiac event associated with Chantix for every 28 smokers they treated with the drug,” the New York Times reported.
“We have known for many years that Chantix is one of the most harmful prescription drugs on the U.S. market, based on the number of serious adverse effects reported to the F.D.A.,” said Dr. Curt D. Furberg, a Wake Forest professor of medicine and senior author of the new report. “It causes loss of consciousness, visual disturbances, suicides, violence, depression and worsening of diabetes. To this list we now can add serious cardiovascular events.”
Dr. Furberg said that there were safer ways for smokers to quit and called for Chantix to be removed from the market.
“It piles up,” Dr. Furberg told the New York Times. “I don’t see how the F.D.A. can leave Chantix on the market.”
The study’s lead author, Dr. Sonal Singh, an assistant professor of medicine at Johns Hopkins University, said that since Chantix gained market approval in 2006, both Pfizer and the FDA have ignored signs that it might be linked to increased cardiovascular risks.
“The F.D.A. should have already put it on their warning label,” Dr. Singh said. “The risk is substantial, the risk is present in smokers without heart disease, and Pfizer knew about this for five years.”
“This would have raised a red flag for us if the flag hadn’t already been flying,” Dr. Celia Winchell, a leader in the FDA’s Center for Drug Evaluation and Research told the New York Times. However, short of a recall, the new findings are likely to have little impact on the FDA’s treatment of Chanitx because the drug already carries the agency’s strongest black-box warnings.
Since its debut, Chantix has been prescribed to 13 million people. Last year, the drug earned Pfizer $775 million in sales.