December 01, 2009


 Phenylbutazone use topic of FDA letter

Posted November 18, 2009

Federal authorities have issued an online statement regarding legal and illegal uses of a nonsteroidal anti-inflammatory drug commonly administered to horses.

The Food and Drug Administration's Center for Veterinary Medicine posted an open letter Oct. 14 to veterinarians on the use and compounding of phenylbutazone in horses.

A complete list of the 48 FDA-approved phenylbutazone, or "bute," products is included, as are reminders of situations under which veterinarians may legally compound the drug. Specific instances are given, such as when a patient requires the drug in a strength or dosage form that is not available among the approved products. In this case, the letter advises using an FDA-approved phenylbutazone product as the starting material and reminds veterinarians that it is illegal to compound the drug from bulk.

Laura Alvey, director of the communications staff at the FDA-CVM, said the agency is aware of reports that phenylbutazone continues to be compounded.

"With the many approved bute products, CVM believed it was important to educate veterinarians and pharmacists alike on the use of the approved products," Alvey said.

Dr. Jim Morehead is a liaison to the American Association of Equine Practitioners Biological and Therapeutic Agents Committee. He said the association appreciates the agency providing clarity on the issue of compounded phenylbutazone.

"Practitioners understand that compounded products do not go through any type of regulated oversight regarding formulation, potency, purity, stability, safety, or effectiveness. They also realize that neither cost nor convenience is a justification for using compounded preparations," Dr. Morehead said.

The letter can be found on the agency's product safety Web site by clicking on the links "Letters to Veterinary Professionals" and "Phenylbutazone in Horses—Veterinarians."