Today, the Food and Drug Administration (FDA) issued an alert to veterinarians and horse owners about adverse events in horses associated with compounds used to treat equine protozoal myeloencephalitis (EPM).
At the center of the FDA’s investigation is a compounded preparation of toltrazuril and pyremethamine. According to the FDA, adverse events including seizures, fever and death were reported to the FDA regarding 10 horses – two horses in Kentucky, and eight horses in Florida. The FDA also reported that of the 10 horses, four have died or have been euthanized and six are currently recovering. The FDA says its testing indicates that one lot of compounds contained levels of pyrimethamine that are higher than indicated in the labeling. According to the FDA, the compounds in lots associated with the adverse events are no longer in distribution. The FDA is working with both the pharmacy and state partners in its investigation.
Any time a compound is a suspected cause of an adverse event, veterinarians are encouraged to report it to the compounding pharmacy, the state board of pharmacy and the FDA Center for Veterinary Medicine.
AVMA continues to remind veterinarians to comply with both FDA’s regulations on extralabel drug use and its Compliance Policy Guide on compounding of drugs for use in animals. AVMA’s Veterinary Compounding policy also reminds veterinarians that use of a compounded preparation should be accompanied by the same precautions followed when using an approved drug, which include counseling of the client regarding potential adverse reactions, including therapeutic failure, and attention to the potential for unintended human or animal exposure to the drug. Further, clients should be informed that the compounded preparation has not been evaluated by the FDA for potency, purity, stability, efficacy or safety, and client consent should be obtained.
Additional information on compounding, including other policies and Frequently Asked Questions, can be found on AVMA’s Compounding webpage.