More evidence has emerged that the stop-smoking drug Chantix slightly raises the risk of heart problems.

The latest analysis of Chantix’s heart risks was published in CMAJ, also known as the Canadian Medical Association Journal. 

Researchers from Johns Hopkins University, Wake Forest University and University of East Anglia reviewed accounts of heart problems among 8,216 participants in 14 previously conducted stop-smoking trials, all but one of which excluded people with a history of heart disease.

As MedPage Today reports, their analysis found that 1.06 percent, or 52, of the 4,908 participants treated with Chantix reported serious adverse cardiovascular results, versus  0.82 percent, or 27, of the 3,308 given placebos.

Dr. Sonal Singh of Johns Hopkins, the lead author, acknowledged that the percentage of participants who suffered serious heart side effects was low. However, based on accounts that 7 million people in the U.S. used Chantix last year, he estimated that 62,500 cardiac events were linked to the drug. “That is not a small number,” he said.

Last month the Food and Drug Administration said it planned to change the label of the Pfizer Inc. drug, known generically as varenicline, to reflect its cardiac risk based on another study of 700 smokers with cardiovascular disease. That study showed that though the pill was effective in helping people quit smoking for as long as a year, it also slightly raised the likelihood of suffering serious cardiac effects.

In an accompanying commentary in CMAJ, Dr. J. Taylor Hays, an associate professor of medicine at the Mayo Clinic who has received research support from Pfizer to study Chantix and whose studies were included in the new analysis, wrote  that the heart problems associated with the drug are low. He added that the risks are “greatly outweighed by the benefits of diminishing the truly ‘heartbreaking’ effects of smoking.”

Pfizer, in a statement, questioned the reliability of the results of the new analysis and said the drug remains “an effective and appropriate treatment option for adult smokers wanting to quit.”

In December, FairWarning reported that an FDA official expressed concerns about the potential heart effects of Chantix at least as far back as 2006.

FairWarning also reported that Pfizer failed in its years of clinical trials to test Chantix on the mentally ill or those with a recent history of depression — even though millions of smokers suffer from psychiatric problems. Since the drug was approved in May, 2006, thousands of Chantix users have suffered serious psychiatric events, including, suicides and depression. The drug carries a black box warning, the FDA’s strongest safety alert.


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