P. Morley, DVM, PhD, Dipl. ACVIM, assistant progessor of epidemiology and biosecurity in environmental health and clinical sciences at Colorado State University, reported on a study involving the effects of furosemide (Salix) on the performance of Standardbred racehorses at the 50th annual American Association of Equine Practitioners (AAEP) Convention in Denver, Colo., Dec. 4-8, 2004. He told the group that positive effects on racing times of Standardbreds had been demonstrated in previous, more limited studies, and that the goal of this research was to use a large number of Standardbreds and to determine whether first-time use of furosemide had a beneficial effect on racing performance.

He said that furosemide is administered to counteract exercise-induced pulmonary hemorrhage (EIPH)–a malady that affects up to 75% of all racehorses to some degree.

Race records for horses at 82 tracks were included in the analysis. Of this number, he said, furosemide was administered to 4,631 horses (22.35%). It was found in the study that more males than females were given furosemide, and that the proportion of horses given furosemide increased with age of the animals.

Overall, Standardbred mares given furosemide, Morley said, finished 0.18 seconds faster than untreated mares; treated geldings finished 0.05 seconds faster than untreated geldings, and treated stallions finished 0.11 seconds faster than untreated stallions