The Food and Drug Administration has once again expanded its recall of widely prescribed blood pressure drugs because of contamination with a chemical linked to cancer.

The latest recall, announced Wednesday, targets 32 lots of the drug losartan sold by Macleods Pharmaceuticals. The pharmaceutical company said that it would voluntarily recall the affected batches.

Losartan is a generic angiotensin II receptor blocker, or ARB, and is used to treat high blood pressure as well as heart failure. Over the last year, scores of batches of generic ARBs have been withdrawn from the market due to the presence of chemical contaminants called nitrosamines, which have been linked to an increased risk of certain kinds of cancer.

“The FDA is continuing to work with manufacturers to swiftly remove medications from the market if they contain” unacceptable levels of nitrosamines, said Jeremy Kahn, an FDA spokesperson. “We’re continuing our investigation as part of our commitment to ensuring adequate and safe supply of ARB medicines for patients.”

Kahn told NBC News that the agency has identified 43 ARB medications that are free of nitrosamine impurities, and that this number is expected to “increase as companies continue to manufacture ARBs without nitrosamine impurities and work to replenish the U.S. supply.”

Patients who are taking an ARB should contact their pharmacist and physician to determine whether the medications they are taking are on the list, said Dr. Sadiya Khan, a cardiologist and an assistant professor of medicine at Northwestern University’s Feinberg School of Medicine in Chicago.

The FDA has compiled a list of contaminated batches that have been recalled. In addition to losartan, two other ARBs have also been affected, valsartan and irbesartan. But Khan suggests people also check with their doctors. “It can be confusing because there are a lot of different formulations of these medications out there and knowing if your medication is on the list is not clear-cut,” she said.

If a patient is currently taking one of the recalled medications, they shouldn’t worry because “there are lots of alternative blood pressure medications that patients can be switched over to,” Khan said. “The most important thing is to not stop your medication without speaking with your doctor because of the dangers of untreated blood pressure.”

High blood pressure and heart failure aren’t the only conditions these drugs are used to treat, Khan noted. Others include “Marfan syndrome and aortic syndrome, where stopping the medications can be even more dangerous,” she added.

Patients taking recalled drugs also shouldn’t worry about cancer risk, because the risk is ultimately low, said Dr. Prashant Vaishnava, a cardiologist and director of quality and inpatient services at the Mount Sinai Hospital in New York City.

While the chemical contaminant in question has been linked to an increased risk of stomach and kidney cancer, “if 8,000 people took the highest dose of the recalled batches for four years, there might be one additional cancer over the lifetime of those 8,000 people,” Vaishnava said.

There are plenty of alternatives to the recalled medications in the same class of drugs, Vaishnava said, and usually, “patients will be alerted by their pharmacist or physician as to whether their medication is affected by the recall.”

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