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.

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.

“Patients have to use this information along with their physicians, and they have to be aware of these risks,” says Sonal Singh, MD, MPH, an assistant professor of medicine and public health at Johns Hopkins University in Baltimore, Md.

“Smoking is a terrible disease. I think people need all options to help them quit,” Singh says.

“What I do with my patients is that I try other options first,” says Singh, who led the 2011 safety review of Chantix. “After you’ve exhausted all other options, and other safer, cheaper options, then you try this. I think that’s very reasonable.”

Other experts agree that the benefits of taking the drug may be worth the risks for people with serious addictions.

“Some people who come to quit smoking, they’re in their 40s or 50s, and they’ve tried to quit many times before with other products, other means,” says Pat Folan, RN, director of the center for tobacco control at North Shore-LIJ Health System in Great Neck, N.Y.

“People have been successful with it,” Folan says. “We’ve had over 400 people use it, and we have not really seen any [bad side] effects with our patients, but it doesn’t mean it couldn’t happen.”

Folan adds that they monitor patients closely if they choose to start the drug.

Advice to Patients

The FDA advises people who are taking Chantix to contact their doctors immediately if they experience any of the following symptoms:

• Shortness of breath or trouble breathing
• New or worsening chest pain
• New or worse pain in legs when walking
• Sudden onset of weakness, paralysis, numbness, or difficulty speaking or understanding speech