It's another blow for Pfizer's stop-smoking drug Chantix. A new study found that healthy, middle-aged smokers who use the drug have a higher risk of having a heart attack or developing other serious heart problems. The meta-analysis of 14 clinical trials found that heart trouble resulting in hospitalization, disability or death was 72 percent more likely in patients using the drug rather than placebo.
Marketed as Champix outside the U.S., the drug has already been subject to safety warnings from the FDA. In 2009, the agency ordered a "black box" warning about the drug's psychological side effects, including suicidal thoughts. Last month, the agency revised Chantix's label to note an increased heart risk for patients who already have cardiovascular disease. But the scientists who conducted the latest study, which included healthy people with an average age of less than 45, said the FDA should take note.
"Our new research shifts the risk-benefit profile of varenicline," lead author Sonal Singh of Johns Hopkins University School of Medicine said in a statement (as quoted by Reuters). "People want to quit smoking to reduce the risk of cardiovascular disease, but in this case they are taking a drug that increases the risk for the very problems they are trying to avoid."
Pfizer disputes the new study, saying the analysis "contains several limitations--most notably that it is based on a small number of events, which raises concerns about the reliability of the authors' conclusions." Together, the 14 studies comprised 8,200 people given either Chantix or placebo; seven in each group died, but the cardiovascular events requiring hospitalization were 72 percent higher in the Chantix group, the researchers said.