FDA Letter Asks Veterinarians to Discontinue Use of Unapproved Aspirin Products in Lactating Dairy Cattle, Potentially Other Species

By Gustavo M. Schuenemann

In October 11, the U.S. Food and Drug Administration (FDA) recently published a “Dear Veterinarian Letter” informing veterinarians and their clients to discontinue use of unapproved aspirin products to treat pyrexia and pain in lactating dairy cattle. A total of 616 confirmed dairy herds in 15 US states were reported positive for highly pathogenic avian influenza (HPAI) as of November 22, 2024. Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) that is being used on some dairy farms to treat cattle infected with HPAI. In the past, FDA considered aspirin products to be of low regulatory concern. However, because the increased use of unapproved aspirin and the availability in the US market of labeled products for treatment of pyrexia (fever) in cattle, the FDA has shifted this stance to state such use as illegal.

The letter states that “The U.S. Food and Drug Administration understands that veterinarians and dairy farmers may be treating lactating dairy cattle for pyrexia and pain with aspirin and wants to clarify that there are no FDA-approved aspirin products for use in cattle”. Furthermore, the letter indicates that “There are FDA-approved products for controlling pyrexia and pain in lactating dairy cattle that are safe, effective, and have established milk and meat withdrawal periods.”

Regarding the use of aspirin products available in the US market, the letter states that “Although other human aspirin products are marketed under an over-the-counter monograph, that monograph is not an approval and, therefore, these products cannot be used in an extralabel manner. 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. The extralabel use of unapproved drug products in food-producing species is prohibited.” On November 1, 2024 the Food Animal Residue Database (FARAD) indicated that aspirin products are not FDA-approved in any veterinary species.

What species are impacted by the FDA letter? Although the letter was issued to veterinarians and their dairy clients, the use of aspirin is also impacting swine and potentially other species.

What should I do if aspirin was accidentally administered to food animals? Please contact and work with your veterinarian. FARAD will work with veterinarians to determine case-by-case withdrawal interval recommendations (milk and meat) following accidental aspirin administration to food animals.

What drug is approved to treat pyrexia and pain in cattle? Banamine transdermal (Flunixin) is the only FDA-approved drug for beef and dairy cattle for control of control of pyrexia (fever) associated with bovine respiratory disease and acute bovine mastitis, and the control of pain associated with foot rot. Additionally, there is one FDA-approved human aspirin product (Vazalore) that is currently marketed and veterinarians might use in food producing species under specific conditions, according to the Animal Medicinal Drug Use Clarification Act (AMDUCA). Please contact your veterinarian for more information.

What does this federal regulatory change mean to you and your livestock operation as well as veterinary practices?

This means that livestock operations would need to establish a veterinary-client-patient relationship (VCPR) to treat animals experiencing pyrexia and pain. Consult your veterinarian for more information. Although there currently are over-the-counter unapproved FDA aspirin products available in the US market, retail suppliers who were able to sell these drugs/products in the past may no longer sell them.

What is a veterinarian-client-patient-relationship?

A veterinarian-client-patient-relationship (VCPR) is defined by the American Veterinary Medical Association as the basis for interaction among veterinarians, their clients, and their patients and is critical to the health of your animal(s). The practical explanation is that it is a formal relationship that you have with a veterinarian who serves as your primary contact for all veterinary services and is familiar with you, your livestock/animals, and your farm operation. This veterinarian is referred to as your Veterinarian of Record (VoR), and both the VoR and the client should sign a form to document this relationship.

Helpful resources:

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; updated on October 29, 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. Aspirin in dairy cattle: Challenges and consideration. Food Animal Residue Database (FARAD). http://www.farad.org/publications/FARAD_Aspirin_DairyCattle_10-24.pdf. November 1, 2024.

Download a VCPR template developed by the Ohio Veterinary Medical Association Drug Use Task Force at: https://extension.vet.osu.edu/general-food-fiber-animal-resources.