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Thyroxine Advisory Released Jointly by RMTC & AAEP

Aug 20, 2020


RMTC/AAEP Thyroxine Advisory

At its February 2020 Meeting, the Racing Medication Testing Consortium’s (RMTC) Board of Directors discussed reports of, and evidence for, the wholesale use of thyroxine in entire populations of racehorses as a ‘wellness’ supplement rather than as the prescription medication that it is.

The Board elected to seek input from, and partner with, the American Association of Equine Practitioners (AAEP) in producing an advisory on the appropriate use of thyroxine by providing education to stakeholders and addressing inappropriate or indiscriminate use of the prescription medication. And in so doing, also preserving the equine veterinarian’s ability to prescribe thyroxine within the context of an appropriate examination and diagnostic testing in an individual horse.

The RMTC’s Scientific Advisory Committee and AAEP’s Racing Committee collaborated in drafting the advisory. During its deliberations the AAEP Racing Committee relied on the principles in the AAEP’s Position on Therapeutic Medication for the Racehorse, particularly the following:

• The AAEP condemns the administration of non-therapeutic or unprescribed medications to racehorses based on our belief that it is not in the interest of horse welfare and racing integrity. (Note: the definition of prescription includes the concept of an individual patient)

• The AAEP believes that all therapeutic medication (prescription or otherwise) should be administered by or under the direction of a licensed veterinarian and based on a diagnosis.

“The health and safety of racehorses are inextricably linked to racing’s integrity, and the drafting of this document has reinforced the AAEP’s and RMTC’s shared priorities of promoting equine health and racing integrity,” Jeff Berk, VMD, Chair AAEP Racing Committee.

About the RMTC

The RMTC is an organization with both scientific and educational purposes, governed by a board of directors representing 23 racing industry stakeholder groups representing Thoroughbred, Standardbred, American Quarter Horse and Arabian racing. The organization’s efforts are focused on research, education and advocacy for science-based initiatives that promote the health and safety of the racehorse and the integrity of competition. For additional information, visit the RMTC website at

About the AAEP

The American Association of Equine Practitioners, headquartered in Lexington, Ky., was founded in 1954 as a non-profit organization dedicated to the health and welfare of the horse. Currently, the AAEP reaches more than 5 million horse owners through its over 9,000 members worldwide and is actively involved in ethics issues, practice management, research and continuing education in the equine veterinary profession and horse industry.