Influence of Long-Term Furosemide Use on Bone Mineral Content, Bone Metabolism Markers, and Water Weight Loss in Horses.

Abstract

Furosemide is used to reduce the incidence of exercise-induced pulmonary hemorrhage in racehorses. Previous research suggests furosemide negatively impacts calcium balance, which may have long-term implications for bone health. Eleven healthy horses, either control (CON, n&#xa0;= 5) or treatment (FUR, n&#xa0;= 6), were used to test furosemide's effects on bone mineral content (BMC), bone metabolism biomarkers, and weight loss after administration. Treatment horses received IV furosemide at 1&#xa0;mg&#x22c5;kgBW once weekly for seven weeks, and blood was collected before and at 24&#xa0;hours after administration for biomarker analysis. All horses were weighed before and at 2, 4, 8, 24, and 48&#xa0;hours after administration. Radiographs of the left third metacarpal were taken every 28&#xa0;days for BMC determination using radiographic bone aluminum equivalence. After administration, FUR lost more BW than CON (P < .05 for all) as quickly as 2 hours after administration (CON:&#xa0;-0.4 &#xb1; 0.3%, FUR:&#xa0;-2.2 &#xb1; 0.3%), and these losses remained greater than CON at 4 hours (CON:&#xa0;-1.0 &#xb1; 0.3%, FUR:&#xa0;-3.3 &#xb1; 0.3%) and 8 hours (CON: 0.0 &#xb1; 0.3%, FUR:&#xa0;-1.2 &#xb1; 0.3%). FUR lost more BW on day 0 than CON (P&#xa0;= .03), but on day 28 and day 49, FUR BW losses were no greater than CON (P > .10). No treatment effects were observed for BMC nor pyridinoline and osteocalcin concentrations (P > .10). Reduced BW changes over time in FUR but not CON warrant further investigation to establish the efficacy of frequent furosemide administration over long periods of time.