When an agency like the Food and Drug Administration (FDA) makes headlines in livestock publications, it might make veterinarians and livestock producers nervous. Recent changes proposed to the way we use cephalosporin drugs in food animals are an example.
Cephalosporins are a class of antibiotic widely used in both human and animal medicine. In people, the more advanced cephalosporin drugs are used to treat pneumonia and other serious infections. Older ones might be used more routinely to treat other infections. It's the close relation of these human antibiotics to animal cephalosporin drugs that has spurred the FDA's proposed changes.
Veterinarians and livestock producers use cephalosporins in the form of familiar injectable drugs like Naxcel®, Excenel®, and Excede®. They are extremely useful drugs for treating respiratory and other illnesses in cattle and pigs. Their very short slaughter withdrawal periods make them very flexible tools to have in our vet box.
So the FDA is worried that overuse of these antibiotics in animals will result in the emergence of bacteria that are resistant to human cephalosporins. Already, these approved injectable products were prescription-only, limiting their use to veterinarians or producers with prescriptions. But it was the “extra-label” uses that FDA became concerned about. Veterinarians by law are able to prescribe uses of approved drugs that aren't specifically spelled out on the label-when they deem it necessary and when a valid veterinary-client-patient relationship (VCPR) is present.
In 2008, FDA proposed to eliminate all extra-label uses of these drugs. This meant that uses such as hatcheries injecting every egg prior to hatching would no longer be possible. But it would also mean that there would be no flexibility for a veterinarian who wished to use these valuable tools to treat an animal with a condition not specifically listed on the label-salmonellosis in a calf, for example.
To their credit, FDA listened to comments from veterinarians and producers back then and realized that a strict ban on extra-label use would severely hamper our ability to help relieve the suffering of individual animals. So their new proposal will keep the provision that allows veterinarians to prescribe cephalosporins for illnesses not specifically listed on the label.
The extra-label uses that will no longer be allowed are changes to dosages, frequencies, or routes of administration. Using cephalosporin compounds that have only been approved for humans or pets will no longer be allowed in food animals. The one proposed change that has spurred the most questions is that use of these drugs for “prevention” of disease will no longer be allowed. I imagine the mass-treatment of healthy animals is what the FDA had in mind here, but in the real world, there are some grey areas. Consider the case of a cattle feeder receiving a load of calves in which a few are already sick with respiratory disease. If his veterinarian decides that the whole group should be treated with a cephalosporin (a commonly accepted practice called metaphylaxis), is that considered disease “prevention” in the animals not yet showing signs of illness? Or is it “control”, which is on the label already? Clearly, regulations that seem black and white to a bureaucrat turn grey in a hurry when people with their boots on the ground try to make heads or tails of them.
Will these rule changes actually do anything to preserve the utility of cephalosporins in human medicine? I'm less than convinced. To me, the link between injecting a steer with Naxcel and a related antibiotic not working in a typical hospital setting is far from certain.
What is certain, however, is that uses of antibiotics in food animals will continue to be scrutinized. Despite the long-standing current rules regarding prescriptions, VCPR's, and extra-label uses, for some, the level of restriction will never be enough. We can likely expect more of these changes in the future; in fact, the approval of new drugs to help animals already has been affected by this mindset. Keeping these critical tools available will mean that all of us involved-producers, veterinarians, drug companies, and governmental agencies-need to use, develop, and regulate these products as responsibly as ever.
Russ Daly, DVM, is the Extension Veterinarian at South Dakota State University. He can be reached via e-mail at email@example.com or at 605-688-5171.