FDA: Off-label use of aspirin in lactating dairy cattle is prohibited

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The FDA recently shared a reminder to veterinarians that using aspirin to treat pyrexia and pain in lactating dairy cattle is prohibited, as there are no aspirin products for use in cattle that are approved by the federal agency.¹ Some dairy farms are using a nonsteroidal anti-inflammatory drug to treat cattle affected by highly pathogenic avian influenza, specifically type A H5N1, according to an American Veterinary Medical Association (AVMA) report that cited communication from the American Association of Bovine Practitioners (AABP) to its members.²

The FDA announcement came in a “Dear Veterinarian” letter, where the agency stated that using unapproved drugs in food-producing species for any off-label purpose is prohibited. According to the FDA, there are safe and effective FDA-approved products for controlling pyrexia and pain in lactating dairy cattle. These products have established milk and meat withdrawal periods. In every FDA-approved animal product, one of the following statements can be found on its label¹:

• “Approved by FDA under NADA # XXX-XXX” (for brand name animal drugs)
• “Approved by FDA under ANADA # XXX-XXX” (for generic animal drugs)

According to the AVMA, flunixin meglumine is the sole FDA-approved medication for managing pyrexia linked to bovine respiratory disease and endotoxemia, and to control inflammation in lactating dairy cattle.²

Off-label drug use in food-producing animals

The Animal Medicinal Drug Use Clarification Act allows veterinarians to prescribe certain FDA-approved human or animal drugs to food-producing animals under defined conditions. These conditions include that no suitable approved animal drug exists for the intended purpose, unless a veterinarian determines, with a valid veterinarian-client-patient relationship, that the approved drug is clinically ineffective for its purpose.³

Moreover, before prescribing an approved animal or human drug for extra-label use in food animals, the veterinarian must conduct a thorough diagnosis, establish extended withdrawal periods for food products, maintain animal identity, and ensure compliance with withdrawal timelines. For approved human drug use, the use must be medically justified, and precautions must be taken to prevent treated animals from entering the human food supply if safety scientific information is unavailable.³

Currently, Vazalore (PLx Pharma) is the only FDA-approved human aspirin available. There are other human aspirin products that are sold as an over-the-counter monograph. However, the monograph did not receive FDA approval, making their extra-label use illegal. “Given the impracticality of dosing cattle with a sufficient amount of the approved human product, the FDA understands that veterinarians and dairy farmers may instead be using unapproved aspirin products that are not legally marketed,” wrote the FDA in its announcement.¹ “The extra-label use of unapproved drug products in food-producing species is prohibited.”

“Veterinarians and dairy farmers should stop use of unapproved aspirin in lactating dairy cattle and use FDA-approved products to control pyrexia and pain,” the FDA continued.¹ “In the event that animals have already been treated with aspirin, veterinarians should use their scientific expertise and available resources to set protective and extended milk and meat withdrawal periods for treated animals.”

References

1. Dear Veterinarian Letter regarding use of aspirin products in lactating dairy cattle. News release. US Food and Drug Administration. October 11, 2024. https://www.fda.gov/animal-veterinary/product-safety-information/dear-veterinarian-letter-regarding-use-aspirin-products-lactating-dairy-cattle
2. FDA warns against use of unapproved aspirin in lactating dairy cattle. News release. American Veterinary Medical Association. October 23, 2024. Accessed October 25, 2024. https://www.avma.org/news/fda-warns-against-use-unapproved-aspirin-lactating-dairy-cattle?utm_source=delivra&utm_medium=email&utm_campaign=todays-headlines-news
3. Animal Medicinal Drug Use Clarification Act of 1994 (AMDUCA). US Food and Drug Administration. Accessed October 25, 2024. https://www.fda.gov/animal-veterinary/guidance-regulations/animal-medicinal-drug-use-clarification-act-1994-amduca#animals