Researchers at the University of Pennsylvania’s School of Veterinary Medicine’s New Bolton Center have planned a multidisciplinary study to explore the effects of the combined use of Lasix and bisphosphonates in racehorses.
Led by Dr. Mary Robinson, assistant professor of veterinary pharmacology and director of the Equine Pharmacology Laboratory at Penn Vet’s New Bolton Center, this landmark study is poised to be the first comprehensive analysis of the two drugs that, when used concurrently could be capable of diminishing bone integrity and compromising cardiac function in racehorses. These effects have the potential to contribute to catastrophic injuries on the racetrack.
“The beauty of this study is that it will use a multi-disciplinary approach to assess the interaction between these two drugs that we know are administered to racehorses,” said Robinson. “By coupling our state-of-the art imaging technologies with the scope of expertise among the other investigators on this project, we will be able to produce solid, unbiased data that will address some of the unknowns surrounding the use of these medications.”
Nearly 85% of racehorses in the United States receive furosemide, commonly referred to as Lasix, to prevent or reduce the severity of exercise-induced pulmonary hemorrhage. Also used in human medicine to treat heart conditions, the drug is known to cause a short-term loss of calcium and increase the risk of fractures in human patients. But because horses can quickly recover from a calcium deficit, the researchers speculate that Lasix alone is unlikely to be the root cause for catastrophic, racing-related breakdowns which, according to The Jockey Club Equine Injury Database, occur at a rate of approximately 1.6 in 1,000 starts.
Bisphosphonates are a group of medicines that slow down or prevent bone loss, strengthening bones. Bisphosphonates inhibit osteoclasts which are responsible for breaking down and reabsorbing minerals such as calcium from bone (the process is known as bone resorption).
Lasix (Salix), also known as furosemide, described as an anti-bleeding medication, is used by veterinarians in horseracing to prevent respiratory bleeding in horses running at high speed. Blood entering the lungs during high physical activity can cause a pulmonary hemorrhage and result in death. It’s no secret that furosemide is both effective in preventing or lessening exercise-induced pulmonary hemorrhage, or that the drug has been shown to make horses lose weight through dehydration—a side effect many people believe makes the substance attractive as a performance enhancer.