Clodronate detection and effects on markers of bone resorption are prolonged following a single administration to horses.

Authors: Knych Heather K, Finno Carrie J, Katzman Scott, Ryan Declan, McKemie Daniel S, Kass Philip H, Arthur Rick M

Journal: Equine veterinary journal

DOI: 10.1111/evj.13866 PubMed: 35871470Log in to save

Summary

# Editorial Summary: Prolonged Effects of Clodronate on Equine Bone Metabolism Clodronate, a bisphosphonate licensed for treating navicular syndrome in horses over four years old, works by suppressing osteoclast activity and bone resorption, yet concerns persist about its use in athletic horses where microfracture repair is critical to soundness and performance longevity. Knych and colleagues administered a single dose of clodronate intravenously to horses and tracked both drug detection in plasma and serum biomarkers of bone resorption (CTX-I and P1NP) over an extended period to establish how long inhibition of bone turnover persists. The researchers found that clodronate remained detectable in circulation considerably longer than previously documented, with suppression of bone resorption markers sustained well beyond what practitioners might anticipate from a single treatment. Given these prolonged pharmacokinetic effects, extra-label use of clodronate in racehorses and other athletic animals warrants careful reconsideration, as the extended inhibition of normal bone remodelling could theoretically compromise the horse's capacity to repair training-induced microdamage and potentially increase fracture risk during the recovery phase.

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Practical Takeaways

•Clodronate's antiresorptive effects persist well beyond a single dose in horses, which may impact bone remodeling and healing in athletic animals
•Extra-label use of clodronate in racehorses and performance horses warrants caution due to potential impairment of natural bone repair mechanisms critical for stress fracture healing
•Practitioners should consider the prolonged systemic effects of clodronate when using it off-label in young or athletic horses requiring normal bone turnover

Key Findings

•Clodronate detection and effects on bone resorption markers are prolonged following single administration in horses
•Concerns exist regarding extra-label use in equine athletes due to potential interference with normal bone healing and microfracture repair
•Long-term pharmacokinetics of clodronate and biomarker effects require further investigation

Conditions Studied

navicular syndrome

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