Efficacy of Common Anti-Ulcer Medications in Racehorses

Gastric ulcers are so common in racing horses that many equine practitioners maintain their racing patients on anti-ulcer medications to prevent and treat gastric ulcers. Reports in the literature place the percentage of racing horses in training with endoscopically visible gastric ulcers at grater than 80%. Unfortunately, despite the variety of anti-ulcer medications available, not all are equally effective at protecting horses from the damaging effects of gastric ulcers. Recently, a study was conducted to compare several anti-ulcer medications used in actively training racehorses to determine which drugs are effective at promoting healing of active ulcers and preventing formation of new ulcers. James Orsini, DVM, Dipl. ACVS, of the University of Pennsylvania's New Bolton Center in the School of Veterinary Medicine, was part of the research team.

Researchers noted that it is difficult to locate racehorses in training not taking anti-ulcer medications. Orsini believes that "approximately 85-90% of Standardbreds and over 90% of Thoroughbreds have gastric ulcers." Therefore, a decision was made to include horses in the study if they had 1) not been receiving treatment for the last two weeks, or 2) had received the same, single anti-ulcer treatment for the last two weeks. During the study, 252 Thoroughbreds and 546 Standardbreds were examined endoscopically by a single examiner to determine gastric ulceration score. The treated horses had received either antacids, sucralfate, misoprostol, an H2 receptor antagonist (cimetidine, ranitidine, famotidine), or omeprazole either compounded (mixed by a pharmacist) or proprietary (from the manufacturer). Horses receiving no treatment served as the control group.

Only the proprietary form of omeprazole (GastroGard) was found to significantly lower the risk of having moderate to severe gastric ulcers. Orsini believes this might be due to the acid-labile (ability to break down acid) properties of this drug, and the fact that the active ingredient tends to degrade when exposed to light and extremes of temperature.

"Proprietary omeprazole, or GastroGard," says Orsini, "has gone through stringent testing and is consistent from tube to tube." It also appears to be the best way to protect horses from moderate to severe ulcer formation during race training.

Orsini is currently involved in the study of antibiotics for use in orthopedic infections, as well as medications for pain management. His other research interests include unlocking the biology of equine skin tumors and hunting for diagnostic markers of equine laminitis.

Orsini, J.A.; Haddock, M.; Stine, L.; et al. Journal of the American Veterinary Medical Association, 223 (3), 336-339, 2003.

About the Author

Susan Piscopo, DVM, PhD

Susan Piscopo, DVM, PhD, is a free-lance writer in the biomedical sciences. She practiced veterinary medicine in North Carolina before accepting a fellowship to pursue a PhD in physiology at North Carolina State University. She lives in northern New Jersey with her husband and two sons.

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