Chantix Linked to Increase in Cardiovascular Events

According to a Canadian Medical Journal report, Chantix, the best-selling prescription drug for smoking cessation, is linked to an increased risk of a heart attack, stroke or other serious cardiovascular event for smokers without a history of heart disease compared with smokers who did not use the drug.

The New York Times reported that Officials of Pfizer, the manufacturer of Chantix, and the Food and Drug Administration responded that they had been planning to conduct a joint analysis of clinical trials on whether Chantix posed heart risks, due next year.

“This would have raised a red flag for us if the flag hadn’t already been flying,” Dr. Celia Winchell, a team leader with the agency’s Center for Drug Evaluation and Research, said in an interview.

Pfizer, in a statement, downplayed the analysis in the Canadian Medical Association Journal stating that the study was underpowered and based on too few heart or cardiovascular events to draw conclusions about the risks. The company further stated that Chantix brought “immediate and substantial” health benefits to smokers who quit.

The senior author of the new report, Dr. Curt D. Furberg, a Wake Forest medical professor, said there were mroe effective and safer ways to stop smoking and called for an FDA recall of Chantix. “It piles up,” he said. “I don’t see how the F.D.A. can leave Chantix on the market.” The lead author, Dr. Sonal Singh, assistant professor of medicine at Johns Hopkins University, said the FDA and Pfizer had both failed to investigate slear signs of cardiovascular risk since Chantix was first approved in 2006.

“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.”

Last month, the FDA issued a safety notice about cardiovascular risk from Chantix use, but the warning was limited to people with a history of cardiovascular disease, based on a study of 700 people. The new report excluded those with a history of heart disease, and analyzed 14 randomized clinical trials involving 8,200 patients. The new study, known as a meta-analysis, compiled data from 14 random, blinded, placebo-controlled clinical trials and found that Chantix had serious cardiovascular events, a rate of 1.06 percent, compared with 27 out of 3,308 people taking a placebo, a rate of 0.82 percent. Although the absolute difference was only 0.24 percent, the weighted, relative difference was 72 percent. This risk transdlates into one extra cardiac event for every 28 smokers treated with Chantix.

“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.,” Dr. Furberg said in a statement. “It causes loss of consciousness, visual disturbances, suicides, violence, depression and worsening of diabetes. To this list we now can add serious cardiovascular events.”