Influence of Long-Term Furosemide Use on Bone Mineral Content, Bone Metabolism Markers, and Water Weight Loss in Horses.
Authors: Pritchard Abby, Spooner Holly, Hoffman Rhonda
Journal: Journal of equine veterinary science
Summary
Furosemide is routinely administered to racehorses to prevent exercise-induced pulmonary haemorrhage, but concerns exist about its effects on calcium metabolism and skeletal integrity during long-term use. Pritchard and colleagues investigated these concerns in eleven horses over seven weeks, with six receiving weekly intravenous furosemide at 1 mg/kg bodyweight and five serving as controls; the team measured bone mineral content via radiographic analysis, tracked bone turnover markers (pyridinoline and osteocalcin), and documented weight changes at multiple timepoints following each dose. Whilst furosemide induced significant acute weight loss—notably 2.2% versus 0.4% at two hours post-administration—this diuretic effect diminished with repeated dosing, and critically, no measurable decline in bone mineral content or disruption to bone metabolism markers occurred over the study period. These findings are reassuring for veterinary practitioners concerned about skeletal consequences of regular furosemide use in competition horses, though the authors appropriately flag that longer-term studies and higher-frequency protocols warrant investigation to confirm safety margins in intensive racing schedules.
Read the full abstract on PubMed
Practical Takeaways
- •Weekly furosemide use in racehorses causes acute water weight loss within 2-8 hours, but this effect normalizes within weeks, which may be relevant for racing weight targets and dehydration concerns
- •Despite concerns about furosemide's impact on calcium balance, this study found no measurable degradation of bone mineral content or bone turnover markers over a 7-week treatment period, suggesting bone health may be more resistant to furosemide than previously feared
- •Long-term efficacy and effects of frequent furosemide administration warrant further investigation before drawing definitive conclusions about safety in performance horses
Key Findings
- •Furosemide-treated horses lost significantly more body weight than controls at 2, 4, and 8 hours post-administration (FUR -2.2% to -3.3% vs CON -0.4% to -1.0%)
- •Body weight losses between furosemide and control groups were not different by day 28 and day 49, suggesting adaptation over time
- •No significant treatment effects were observed on bone mineral content or bone metabolism markers (pyridinoline and osteocalcin) after 7 weeks of weekly furosemide administration