Pharmacokinetics of orally administered calcium dobesilate in Warmblood horses.
Authors: J. Harder, A. Fürst, P. M. Montavon, S. Montavon, M. Bakony, K. Lányi
Journal: Schweizer Archiv fur Tierheilkunde
Summary
Calcium dobesilate is increasingly used in equine practice to manage lameness conditions involving compromised microvascular perfusion and elevated intraosseous pressure—particularly navicular disease, bone cysts and pedal oedema—but until now its oral bioavailability in horses remained unconfirmed. Harder and colleagues administered 3 mg/kg of the compound orally to eight healthy Warmbloods twice daily for a week, then measured plasma concentrations of its active metabolite (2,5-dihydroxybenzene sulfonate) using liquid chromatography following the final dose. The drug was successfully absorbed across the equine gastrointestinal tract, generating detectable plasma concentrations ranging from 2300–3600 ng/ml (mean 2900 ng/ml), with no adverse effects or haematological changes observed. For practitioners considering calcium dobesilate as part of a conservative management strategy for conditions driven by poor bone perfusion, this finding validates that oral dosing achieves systemic exposure; however, the study's limitation to sampling only post-treatment and analysis of plasma alone leaves questions about optimal dosing intervals, tissue penetration and sustained therapeutic levels that future work should address.
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Practical Takeaways
- •Calcium dobesilate is absorbed orally in horses and reaches therapeutic plasma levels, making it a viable option for treating navicular disease and bone-related lameness conditions.
- •Oral administration in mash appears to be an effective and practical delivery method with no reported adverse effects, though longer-term safety and efficacy data are still needed.
- •This pharmacokinetic data supports further clinical trials to evaluate whether calcium dobesilate's microvascular and intraosseous pressure-reducing properties translate to improved healing outcomes in lameness cases.
Key Findings
- •Calcium dobesilate (3 mg/kg PO q12h) was absorbed by the equine GI system and achieved detectable plasma concentrations of 2,5HBSA (mean 2900 ng/ml, range 2300-3600 ng/ml) after oral administration in mash for 7 days.
- •No adverse effects occurred during the 7-day treatment period and all haematological and plasma biochemical parameters remained within reference limits.
- •The active metabolite 2,5-dihydroxybenzene sulfonate (2,5HBSA) was consistently detectable in plasma after the final dose, confirming oral bioavailability of calcium dobesilate in horses.