Heart Warning Added to Pfizer’s ‘Z-Pak’ Antibiotic by FDA

Doctors should be aware of potential risks to patients with heart conditions when prescribing the antibiotic azithromycin, U.S. regulators said.

The Food and Drug Administration today updated the labeling information on the drug to reflect increased risk of fatal irregular heartbeats in patients. Research published last year found that the pills, used to treat infections, caused a small increase in cardiovascular deaths, especially among people with a higher risk of heart problems.

“Health-care professionals should consider the risk of fatal heart rhythms with azithromycin when considering treatment options for patients who are already at risk,” the FDA said in a statement today on the label change. The agency said azithromycin isn’t alone in carrying heart risks.

Zithromax is made by Pfizer Inc., the world’s largest drugmaker, and multiple generic manufacturers, and sometimes goes by the names Zithromax, Zmax or Z-Pak. The medicine generated about $435 million for New York-based Pfizer in 2012. It’s prescribed to treat bacterial infections of the respiratory system and urinary tract and for tonsillitis.

Pfizer has updated the label on the drug, said Lauren Starr, a company spokeswoman.

“The majority of patients treated with Zithromax (azithromycin) are not affected by this label update,” Starr said in an e-mail. The drug “has had a well established benefit risk profile for more than 20 years and continues to be an effective treatment option for patients all over the globe suffering from many types of bacterial infections.”

Pfizer fell 1.1 percent to $27.94 at the close in New York.

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