Clodronate, a bisphosphonate medication, has become a popular treatment for navicular disease despite little understanding of how it affects the bones of horses.
This blinded randomized controlled trial examined the effects of the drug on lameness, as well as bone turnover markers in the blood. Twelve competition school horses with a known history of navicular disease were used for the trial. Blood and bone marrow samples were used to measure bone turnover markers. Bone cell recruitment and lameness and the coaches’ impressions of lameness and performance were assessed periodically throughout the study.
There were no differences in bone cell recruitment or bone turnover markers between the treatment and control groups. There was a small improvement in lameness noted for clodronate treated horses, and coaches were more likely to report an improvement in performance for treated horses compared with controls. The authors are quick to point out that this study only examined the effects of a single treatment, while in practice many horses receive multiple doses of the drug over time. However, the results of this study do suggest that a single treatment may improve lameness and does not appear to have adverse effects on bone activity at the cellular level.
— Mitchell A et al. EVJ 2019;51:356-363