Early this past April, the Food and Drug Administration cracked the whip at a New York-based veterinarian whose drug prescriptions resulted in illegal residues in two animals intended for food. The FDA detected the residues when the animals were submitted for slaughter, only days after being given the drugs. The agency issued a warning letter to the veterinarian and told him to promptly establish procedures to avoid repeating the mistake, or risk further regulatory action, including injunction, fines, or even jail time.
While the percentage of violative residues is very low, incidents like this occur and illustrate that big brother, the National Residue Program, is watching. The National Residue Program, which has been in effect since 1967, is tasked with keeping residues that could be harmful to humans out of the food system.
Three agencies are responsible for controlling residues in meat, poultry, and egg products: the Department of Agriculture's Food Safety and Inspection Service, Environmental Protection Agency, and FDA. The FDA and EPA establish maximum permissible levels for chemical residues in foods. The FSIS enforces these tolerances through its various control programs, including random testing of animals at slaughter. The FDA hands out penalties for infractions.
Gloria Dunnavan, director of the Division of Compliance at the FDA Center for Veterinary Medicine, says that, for the most part, veterinarians and producers who receive warning letters respond quickly and fix the problem. "I'm not aware of any veterinarians that have actually reached the point of prosecution," Dunnavan said. "They are educated and they generally get the point. We've occasionally prosecuted livestock dealers (who are) repeat offenders." Most people get the message—the FSIS lists only three repeat violators on its Web site.
Although the FDA does not hand out harsh penalties often, the number of warning letters indicates a problem exists. According to the FDA's Web site, between this past November and April, the agency sent warning letters to 31 producers for illegally using drugs in food animals. Each letter covered multiple infractions. During this six-month period, three veterinarians and one veterinary drug sales facility also received warning letters. These, however, are just the people who were caught.
In some cases, illegal residues exist because individuals did not use correct withdrawal times. In others, the drugs were given at a higher dosage than that specified on the label. And in still other situations, certain antimicrobials are being used incorrectly within a species.
Fluoroquinolones, for example, are specifically prohibited for use in cattle intended for dairy production. The FDA, however, has had to warn veterinarians in Michigan, Texas, Vermont, and Washington who have prescribed the drug for this exact purpose. Food and Drug Administration representative Dr. Douglass Oeller noted these violations at the AVMA Clinical Practitioners Advisory Committee meeting this past March.
The prohibition on use of fluoroquinolones, including the newly approved drug A180, applies to all classes of cattle on a dairy farm operation, including calves reared as dairy cow replacements, heifers, lactating and nonlactating cows, and bulls maintained for breeding purposes. Because of human safety concerns, fluoroquinolones cannot even be stored in the milk house, milking barn, stable, or parlor.
"One of the classes of animals that often present with illegal residues are culled dairy cows," Dunnavan said. "They are usually culled because of some health issue—they are sick or not producing well."
This is what happened in the previously mentioned New York-based case. In an attempt to treat pneumonia in two dairy cows, the veterinarian used a solution containing flunixin in one dairy cow and penicillin G procaine in another. Both actions resulted in illegal residues at slaughter.
Respecting residue regulations
Under the Animal Medicinal Drug Use Clarification Act, veterinarians are prohibited from prescribing certain drugs in an extralabel manner. Drugs that cannot be used in an extralabel manner include chloramphenicol; clenbuterol; diethylstilbestrol; dimetridazole, ipronidazole, and other nitroimidazoles; furazolidone, nitrofurazone, and other nitrofurans; sulfonamide drugs in lactating dairy cattle (except approved use of sulfadimethoxine, sulfabromomethazine, and sulfaethoxy-pyridazine); fluoroquinolones; glycopeptides; and phenylbutazone in female dairy cattle 20 months of age or older. Phenylbutazone is the most recent newcomer, joining the list on May 29, 2003 (see JAVMA, April 15, 2003, page 1059).
According to Dunnavan, veterinarians have a responsibility not only to follow the regulations themselves, but also to educate their clients to make sure they are compliant. In many cases, the client may actually be administering the drug.
Some clients attempt to follow the rules, but then make mistakes. In a warning letter to a Wisconsin farm owner, the FDA chastises him for recording the drug treatment of a dairy heifer on a calendar, but then absent-mindedly throwing away the calendar.
The FDA thinks veterinarians should be proactive. "You need to spend some time with (your) client, making sure they understand to follow the label directions, and that if they finish the treatment regimen, and they have some drug left over, to not use it on some other animal," Dunnavan said.
In addition to providing education on drug use, veterinarians need to educate producers about keeping the required records. These include identifying the exact animals treated and for which conditions, the established name of the drug used and its active ingredient, the dose prescribed, the duration of treatment, and the specified withdrawal, withholding, or discard times. The FDA recommends maintaining these records for two years.
"Those are some basic common-sense things, but it's really important for the veterinarian to engage in that dialogue with their client," Dunnavan said. "They are pretty simple, basic management practices that are not hard to institute. The producers do listen to their veterinarian."
The FDA hopes that by continuously repeating the message and walking the compliance cop beat, they will eventually reach all involved parties. "This is a long-standing program," Dunnavan said. "We do take a lot of time and effort to try to educate all the involved parties in this effort."