spangled banners yet wave? captioning sponsored by cbs this is the cbs evening news with scott pelley. pelley: good evening, chantix is the most popular anti-smoking drug on the market with annual sales of nearly $800 million. but a study out today raises new safety questions about it. chantix has already been linked to an increased risk of suicidal thoughts and now to a higher risk of heart disease we asked dr. jon lapook to tell us what we need to know about these new findings. reporter: today s study is worrisome news for the more than seven million americans who have taken chantix. a new analysis links the pill to a 72% increase in the risk of heart problems. johns hopkins dr. sonal singh led the research. it is causing the same problems we are trying to prevent, that s why it s not worth the risk. we need to prevent cardiac disease among smokers, not increase it. reporter: the review involves more than 8,000 patients. while a 72% increased risk sounds alarming,