In thoroughbred horse racing, “Bute” is the common term for phenylbutazone, a non-steroidal anti-inflammatory drug (NSAID) used to treat pain and inflammation in horses. This medication is probably the most widely used drug in horses and serves as an inexpensive, highly effective treatment for various conditions.
Bute is prescribed by veterinarians for lameness resulting from soft tissue injury, muscle soreness, bone and joint problems, and laminitis. It works by blocking the effects of prostaglandins and inhibiting cyclooxygenase (COX) enzymes, which reduces the body’s ability to produce inflammation. The drug can be administered intravenously or given orally to horses as a powder or paste.
The use of bute in racing raises significant questions about fairness to both horses and competitors. While it doesn’t directly enhance performance, bute can effectively relieve pain and mask the effects of injuries, essentially allowing an injured horse to compete as their normal self. This capability to treat symptoms rather than causes means it’s NOT a cure for underlying conditions.
A key concern in racing is bute’s rapid metabolism in horses—it has a biological half-life of only 6 hours in horses compared to 72 hours in humans. This means bute can be given to a horse fairly soon before a performance with minimal chances of detection.