WASHINGTON – The US Food and Drug Administration (FDA) said the agency is taking steps to rescind approval of carbadox to treat swine because the drug may leave trace amounts of cancer-causing residue. Phibro Animal Health of Teaneck, New Jersey, manufactures carbadox, which is used to treat bacterial infections in swine.

The agency’s Center for Veterinary Medicine (CVM) began the process of withdrawing its approval of the drug following a re-examination of the drug’s safety profile. A preliminary risk characterization revealed the “potential risk to human health from ingesting pork, especially pork liver,” harvested from pigs treated with carbadox.

“The manufacturer of carbadox has failed to provide sufficient scientific data to demonstrate the safety of this drug given evidence that carbadox may result in carcinogenic residues,” Michael R. Taylor, FDA deputy commissioner for foods and veterinary medicine, said in a statement. “As a result, FDA’s Center for Veterinary Medicine is taking legal action to remove this product from the marketplace.”

However, FDA said the agency is not recommending consumers make changes to their diet, noting that potential cancer risks “are based on an assumed lifetime of consuming pork liver or other pork products containing carbadox residues…” Short-term changes to consumers’ food choices are unlikely to affect an individual’s lifetime risk.

“However, removal of the product from the market will reduce the lifetime risk to consumers, which is why CVM is taking this action,” FDA said. “Pork liver is used to make liverwurst, hot dogs, lunchmeat and some types of sausage. In general, eating a varied diet may reduce the potential negative effects of eating too much of any one food.”

FDA first approved carbadox in the early 1970s to control swine dysentery and bacterial swine enteritis. The drug also has been used as a growth and feed efficiency-promoting drug in swine feed. But the Codex Alimentarius Commission determined in 2014 there are no save level of residues of carbadox or its metabolites in food.

Phibro has 30 days to request a hearing on whether approval should be withdrawn. Otherwise, FDA can proceed with steps to remove the drug from the market.