Efficacy of furosemide for prevention of exercise-induced pulmonary hemorrhage in Thoroughbred racehorses.
OBJECTIVE
To evaluate the efficacy of furosemide for prevention of exercise-induced pulmonary hemorrhage (EIPH) in Thoroughbred racehorses under typical racing conditions.


METHODS
Randomized, placebo-controlled, blinded, crossover field trial.


METHODS
167 Thoroughbred racehorses.


METHODS
Horses were allocated to race fields of 9 to 16 horses each and raced twice, 1 week apart, with each of the 2 races consisting of the same race field and distance. Each horse received furosemide (500 mg, IV) before one race and a placebo (saline solution) before the other, with the order of treatments randomly determined. Severity of EIPH was scored on a scale from 0 to 4 after each race by means of tracheobronchoscopy. Data were analyzed by means of various methods of multivariable logistic regression.


RESULTS
Horses were substantially more likely to develop EIPH (severity score >or= 1; odds ratio, 3.3 to 4.4) or moderate to severe EIPH (severity score >or= 2; odds ratio, 6.9 to 11.0) following administration of saline solution than following administration of furosemide. In addition, 81 of the 120 (67.5%) horses that had EIPH after administration of saline solution had a reduction in EIPH severity score of at least 1 when treated with furosemide.


CONCLUSIONS
Results indicated that prerace administration of furosemide decreased the incidence and severity of EIPH in Thoroughbreds racing under typical conditions in South Africa.
Hinchcliff
Kenneth W
KW
Faculty of Veterinary Science, University of Melbourne, Melbourne, VIC 3030, Australia.
Morley
Paul S
PS
Guthrie
Alan J
AJ
D000818:Animals; D004232:Diuretics / Q000627:therapeutic use*; D005260:Female; D005665:Furosemide / Q000627:therapeutic use*; D006470:Hemorrhage / Q000517:prevention & control / Q000662:veterinary*; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D008171:Lung Diseases / Q000517:prevention & control / Q000662:veterinary*; D008297:Male; D010805:Physical Conditioning, Animal / Q000009:adverse effects*
D004232:Diuretics; D005665:Furosemide