A U.S. District Court Judge has ordered the Food and Drug Administration (FDA) to restart proceedings initiated in 1977 to evaluate the safety of using penicillins and tetracyclines to fatten livestock.
Judge Theodore H. Katz of the Southern District of New York ruled March 22 that the FDA must propose a ban on such uses of the drugs, and give drug manufacturers the opportunity to present evidence that so-called "production uses" — feeding antibiotics to livestock so that they grow slightly faster or require less feed to reach market weight — are safe.

Antibiotics used for this purpose typically are administered in feed at low doses to entire herds or flocks of animals. A veterinary prescription is not required. Basic biology indicates that these uses generate antibiotic-resistant microbes, but the risk these pathogens pose to human health has not been well quantified.

The FDA proceedings would not affect the use of penicillins and tetracyclines for disease prevention, control and treatment in livestock or other animals.

The prevalence of growth promotion uses of antibiotics is unclear because the government does not collect data on the quantities of antibiotics sold for that purpose versus for the prevention, control and treatment of disease. However, U.S. Department of Agriculture reports suggest that growth promotion uses amount to millions of pounds annually.

In response to concern about antibiotic resistant pathogens, the FDA first issued a regulation in 1973 providing for the withdrawal of "subtherapeutic" uses of antibiotics in animal feed unless manufacturers could establish that such uses are safe. In 1977, the agency reached a formal finding that production uses are not safe and issued notice of opportunity for hearing (NOOH) on banning such uses. A date for the hearing was never set and the agency did not move forward with the proceedings, despite the fact that, as Katz noted in his opinion, "the FDA has not issued a single statement since the issuance of the 1977 NOOHs that undermines the original findings that the drugs have not been shown to be safe."

In May 2011, a coalition of environmental and public health groups sued the FDA seeking to compel the agency to move forward with the withdrawal, launching the legal proceedings that led to Katz's decision. 

FDA lawyers argued, among other things, that moving forward with the withdrawal hearings would interfere with ongoing discussions between the agency and livestock, pharmaceutical and veterinary medical groups that are expected to lead to some restrictions on antibiotic use on farms. Katz rejected that argument.

In an American Veterinary Medical Association (AVMA) news release issued Wednesday, Dr. Ron DeHaven, the group's chief executive, said AVMA "acknowledges the growing concern regarding antimicrobial use and resistance in animals and people, and supports the judicious use of antimicrobials to maximize public and animal health benefits while minimizing risks.” The release did not take a position on the use of antibiotics for production purposes but stated, "It is crucial that safe and effective antimicrobials remain available for use in veterinary medicine to ensure the health and welfare of animals and, consequently, the health of humans."

DeHaven also noted that the AVMA continues to work with the FDA to craft regulations expanding veterinary oversight over the use of antibiotics in the meat, dairy and poultry industries. The New York Times reported March 23 that the FDA is expected to release a draft version of these rules "within days." Currently, many on-farm uses of antibiotics require no prescription or other veterinary oversight.