"The use of medication in horses competing at equestrian events is a very polarizing topic," said Marjorie W. Miller, DVM, an equine veterinarian from Bradenton, Fla., with 20 years experience in performance horse practice."Some people believe that medication has no place in equestrian sports, and others believe that the judicious use of medication is in the best interest of equine health and welfare."

At the 2010 American Association of Equine Practitioners Convention, held Dec. 4-8 in Baltimore, Md., Miller discussed medication rules from several equestrian governing bodies as well as the role of veterinarians in equestrian sport.

National and International Rules

Miller began by reviewing the United States Equestrian Federation (USEF) medication definitions. A forbidden substance is anything that "contains an ingredient or a drug that might affect the performance of a horse or pony by acting as a stimulant, depressant, tranquilizer, local anesthetic, or psychotropic (a mood- and/or behavior-altering substance), is potentially dangerous to the horse, or interferes with drug detection procedures." By definition, even products claiming to be nontestable at USEF competitions are illegal by virtue of their claims to alter performance