The Commission has been notified of greyhounds being treated with a class of drugs called Bisphosphonates (BPs). Scientific evidence suggests the use of these drugs may increase the risk of bone fractures.

Bisphosphonates come under a variety of brand names such as Tildren (Tiludronic acid), and Zometa, Reclast (Zoledronic acid), just to name a few.

Under the NSW Greyhound Racing Rules, all Bisphosphonates are prohibited substances. Currently there are no known withholding periods for such drugs in greyhounds.  However, in racehorses unpredictable excretion and prolonged detection periods of several years have been seen.  Use of bisphosphonates therefore may carry a risk of the greyhound returning a positive swab long after the drug was administered.

Bisphosphonates are widely used in humans with osteoporosis, to improve bone density. However BPs are not registered for use in dogs.

The veterinary use of such medications is primarily aimed at curbing bone cancer pain.

However, canine studies have demonstrated that although Bisphosphonates may increase bone density, the resultant reduction in bone turnover (a biological process of removing old bone and replacing it with new bone) is associated with an increase in micro-crack accumulation, increased bone brittleness, and significantly reduced bone toughness (Mashiba et al., 2010; Burr et al., 2015). This may predispose the dog to bone fracture.

As Bisphosphonates are also believed to have anti-inflammatory and pain-relieving effects, masking pain when underlying bone micro stresses fractures exist could increase the risk of serious injury.

The inappropriate use of Bisphosphonates poses a significant welfare risk to racing greyhounds, and all trainers are strongly urged to avoid using them.

Allen, R.A., Burr, D.B. (2011). Bisphosphonate effects on bone turnover, microdamage, and mechanical properties: What we think we know and what we know that we don't know. Bone, 49(1), 56-65.

Burr, D. B., Liu, Z., & Allen, M. R. (2015). Duration-dependent effects of clinically relevant oral alendronate doses on cortical bone toughness in beagle dogs. Bone, 71, 58–62. https://doi.org/10.1016/j.bone.2014.10.010

Mashiba, T., Hirano, T., Turner, C.H., Forwood, M.R., Johnston, C.C. and Burr, D.B. (2000). Suppressed bone turnover by bisphosphonates increases microdamage accumulation and reduces some biomechanical properties in dog rib. Journal of Bone and Mineral Research, 15, 613-620. https://doi.org/10.1359/jbmr.2000.15.4.613

If you have any questions regarding this health warning, please contact us via vets@gwic.nsw.gov.au or call 13 49 42 (13 GWIC).