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Science‐in‐brief: Bisphosphonate use in the racehorse: Safe or unsafe?
Author(s) -
McLellan J.
Publication year - 2017
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12682
Subject(s) - medicine , bone remodeling , bisphosphonate , horse , osteoporosis , paleontology , biology
Bone remodelling is of great importance to several orthopaedic diseases of the Thoroughbred racehorse, and bisphosphonates, with their reported effects on bone turnover, may have the potential to alter the remodelling response. The USA recently approved 2 non-nitrogenous members of the bisphosphonate drug family, clodronate and tiludronate, for treatment of navicular disease in the horse. Tiludronate, having already been licensed for similar use in several European countries, was previously available to veterinarians in the USA through Food and Drug Administration approved importation on a case-by-case basis. Currently, commercial advertisements for these recently licensed non-nitrogenous bisphosphonates appear in veterinary specific and, in the USA, general horsemanship publications. Nitrogenous bisphosphonates are not yet licensed in the horse but there are anecdotal reports of their off-label use in the racehorse. With the increasing awareness of bisphosphonates amongst racehorse trainers, owners and veterinarians, it is prudent to examine the existing evidence to determine if this class of drugs has a place in the off-label treatment of orthopaedic disorders of young and/or racing Thoroughbreds. In bone, the osteoclast-related antiresorptive effect of bisphosphonates is well documented [1]. The simple assumption that “by inhibiting osteoclasts we stop bone resorption, which means bones are stronger” is a gross oversimplification of bone physiology and drug pharmacology. Bisphosphonates have additional anti-inflammatory and pain relieving effects, in addition to effects in nonosseous tissue such as cartilage. Practitioners must have answers to the following questions prior to embarking in off-label bisphosphonate treatment of the young or racing Thoroughbred: What is the current evidence for use in horses? What conditions of racehorses have anecdotally been suggested for off-label treatment with these drugs and does the evidence support such use? Are there known or theoretical longer term risks to treatment? Finally, can bisphosphonates be safely used in immature horses?