A so-called best-seller prescription drug Chantix, which is mainly used to end one's smoking habit, was linked to an increased risk in heart attacks, strokes and related cardiovascular diseases for smokers, according to a report released in a Canadian journal on Monday.

In the report published by the Canadian Medical Association, smokers who did not use the drug were compared to individuals who suffered from heart-related diseases. Researchers, who reviewed 14 studies on Chantix, found a 72 percent increase in the cases compared to smokers taking a placebo.

The United States Food and Drug Administration, along with officials from Pfizer, maker of Chantix, told reporters that they plan to conduct a joint analysis of clinical trials of Chantix, which has been prescribed to at least 13 million smokers and made $755 million in sales last year in 2011 - to see whether it causes heart risks to its users.

This would have raised a red flag for us if the flag hadn't already been flying, Dr. Celia Winchell, team leader for the agency's Center for Drug Evaluation and Research division, told The New York Times, in an interview.

However, Pfizer, in a statement, said their analysis was based on too little of heart or cardiovascular cases to draw conclusions about the risks. Chantix potentially brings immediate and substantial health benefits to those who use their drug - smokers who quit, according to the drug manufacturer.

Dr. Curt D. Furberg, a Wake Forest medical professor and lead author of the new report, said there were better ways to quit and called for removal of the drug from the market. It piles up, he added. I don't see how the FDA can leave Chantix on the market.

The report complements previous warnings about the pill's connection to mental problems and cardiovascular risks for smokers with a history of heart disease.