The U.S. Food and Drug Administration is investigating whether a compounded medication might have played a role in the deaths of two Thoroughbred horses and sickening several others, said Cariny Nunez, a representative from the administration's Miami office.

Robert MacKay, BVSc, PhD, Dipl. ACVIM, professor of Large Animal Medicine at the University of Florida College of Veterinary Medicine, said in a statement that eight Thoroughbreds received a single dose of a compounded toltrazuril/pyrimethamine drug, from the Wickliffe Veterinary Pharmacy, in Lexington, Kentucky, to treat equine protozoal myeloencephalitis (EPM). The horses, which resided at a training stable in Ocala, Florida, began exhibiting neurologic disturbances within 36 hours of administration, he said.

Wickliffe Pharmacy said it adheres to the highest safety, quality, and validation standards and knows of no correlation between its compound and the reported adverse events. The company said it will work to determine the cause of the adverse events.


"Wickliffe was recently informed of adverse events involving horses that received a toltrazuril/pyrimethamine suspension compounded at its pharmacy. There is no known correlation between Wickliffe's compound and the reported adverse events," the company said in a release. "Wickliffe is working cooperatively with health authorities to determine the cause of the adverse events as quickly as possible. Wickliffe has no indication that the preparation compounded at its phar