Common pig antibiotic may cause cancer in humans who eat pork

Carbadox, a drug manufactured by Phibro Animal Health in New Jersey, is used to fight infections in pigs such as swine dysentery and bacterial enteritis. It is also used to support faster weight gain. Sold under the brand name Mecadox, the drug is now the target of a U.S. Food and Drug Administration (FDA) investigation that has concluded that carbadox has the potential to leave carcinogenic residue traces in pork, posing a risk of cancer to people who eat it. On April 8 the FDA took the first step toward rescinding the approval for the drug and removing it from the market.

The FDA’s Center for Veterinary Medicine (CVM) took the action after recently reexamining the safety of the drug and conducting a preliminary risk assessment. In a news release, the FDA said that Phibro had “failed to provide sufficient scientific data to demonstrate the safety of this drug given evidence that carbadox may result in carcinogenic residues.”

At this time the CVM is not recommending that people change their diet in order to avoid pork. The potential cancer risks are based on an assumption of a lifetime of consuming pork, particularly pork liver, a common ingredient in products such as liverwurst, lunchmeat, hot dogs and sausage. They said that short-term dietary changes are not likely to affect a person’s lifetime risk. However, the CVM has determined that removing carbadox from the market could reduce the lifetime risk to consumers.

Phibro officials insist that the drug is safe. In a statement the company said, “Mecadox has been approved and sold in the United States for more than 40 years and is a widely-used treatment for controlling bacterial diseases.” However, Phibro has not responded to an FDA request for additional information about the safety of carbadox.

Phibro is undertaking what it describes as “comprehensive, rigorous new studies” of the drug using the “latest and most sensitive technology available.” These studies are expected to be completed within 90 days, and Phibro fully expects that the evidence will support that the drug is safe to use.