Study Questions Safety Of Chantix

Millions of Americans have used the drug Chantix to help them quit smoking.  But now a new study in the Canadian Medical Association Journal is raising safety questions about the drug.

The study finds that middle-aged smokers who use the drug have a 72 percent increased risk of heart attack or other serious heart problems.  The Food and Drug Administration has raised concerns about Chantix for smokers with existing heart disease, but the study says it also puts healthy smokers at risk. 

"We quit smoking to reduce the risk of cardiac disease, not to increase it," study author, Dr. Sonal Singh, said.

Pfizer, the maker of Chantix, disagrees with the findings. The drug does carry a warning for side effects, which includes depression and suicidal thoughts.

In light of the new study, the FDA is calling for more research.  Chantix had U.S. sales of $360.6 million in 2010.