Dec. 14, 2012 -- Smokers who take Chantix to stop smoking may be at higher risk for heart attacks and strokes compared to those who don’t take the drug, the FDA says. But the increased risk is small and should be weighed against the risks of continuing to smoke.
Chantix is the top-selling smoking cessation drug in the U.S., according to IMS Health. It works by blocking the effect of nicotine in the brain. Studies have shown that about 20% of people who take Chantix quit smoking long-term compared to 10% of those who take placebos.
But the medication has also been dogged by safety questions. The drug’s label carries a black box warning about mood changes that may lead to depression and suicide.
Last year, the FDA issued a warning about heart risks tied to the drug and ordered Pfizer, the company that makes Chantix, to conduct additional safety studies.
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New Safety Data on Heart Risks
The updated safety review included more than 7,000 smokers. Those who took Chantix for three months suffered more major cardiac events -- those included deaths due to heart problems as well as heart attacks and strokes that weren’t fatal -- than those who took a placebo.
But heart problems were rare in both groups. Just 13 out of 4,190 people (or 0.31%) who took Chantix suffered a major heart event compared to six out of 2,812 people (or 0.21%) who were taking a placebo.
The difference between the two groups may have simply been due to chance and not to any real effect of the drug.
“However, the data were analyzed many different ways and consistently showed a higher occurrence of events in patients using Chantix, which makes it seem more likely that it is related to the drug and not purely a chance finding,” says the FDA report.
A similar study, published last year in the Journal of the Canadian Medical Association, of 14 clinical trials involving 8,216 people, also found increased heart problems in smokers who took Chantix compared to those on a placebo. In that study, which used a broader definition for heart problems that included episodes of chest pain, the findings were strong enough not to be chance.
But the absolute risk of having a heart problem in either group was still low: About 1% of people had heart problems in the Chantix group compared to 0.8% in the placebo group.
Weighing Benefits and Harms
Experts say the bottom line is that smokers should carefully weigh the risks and benefits of taking the drug against the risks of smoking. Smokers have two to four times the risk of developing heart disease compared to nonsmokers, according to the CDC.