Pfizer stands by Chantix

NEW YORK — Pfizer defended a drug used for smoking cessation Monday following reports of a Canadian study that found it raised the risk of heart problems.

The 8,216-patient study of Chantix (varenicline), published in the Canadian Medical Association Journal, found that of the 4,908 patients who received Chantix, 52 had an increased risk of serious heart problems, with similar risks appearing in 27-of-the-3,308 patients who took placebo.

Pfizer responded by pointing out that the authors of the study said the cardiovascular risk “estimates are imprecise owing to the low event rates.”

“Pfizer scientists and doctors continuously evaluate the benefits and risks of its medicines, including Chantix,” Pfizer VP medical affairs Gail Cawkwell said. “The currently available safety data on Chantix, including a pooled analysis of clinical data in 7,375 people trying to quit smoking, do not support an increased cardiovascular risk associated with Chantix.”

Still, the study’s findings won’t do the drug any favors. In 2008, the Federal Aviation Administration banned its use by pilots and air-traffic controllers after it was found to increase the risk of depression and suicidal thoughts and behaviors, and the Food and Drug Administration ordered that it carry a boxed warning, the strongest possible safety label, in 2009.