Should Furosemide be used in racehorse to avoid exercise induced pulmonary hemorrhage (EIPH) ?

Author: Aisha Javed
(DVM, UAF)

Is it worth using furosemide to avoid exercise induced pulmonary hemorrhage (EIPH) in racehorses? Furosemide has been used empirically and has been used legally approved for many years by US racing industry for control and treatment of horses that bleed, a condition known as exercise induced pulmonary hemorrhage (EIPH) that leads to epistaxis. Its use for EIPH treatment in horses is highly controversial and has been criticized by organizations outside and inside of racing industry. Read articles and latest advancements in the field of poultry by visiting our poultry section

Faster horses are affected more than slower ones

Furosemide a diuretic that’s been used since the early 1970’s to prevent or diminish EIPH severity in race horses. EIPH was first recorded in literature in late 1700’s when it was identified as epistaxis after intense exercise and decrease in performance. Fiberoptic endoscope was invented in 1970’s that veterinarians found that up to 80% of racehorses had evidence of bleeding in their trachea after race. Then, bronchoalveolar lavage show evidence of bleeding at alveolar capillary level. Latter this condition known as EIPH.

Applied pharmacology of furosemide to avoid EIPH:

Furosemide most commonly used drug to prevent EIPH despite the lack of a clear rationale for its use . Pulmonary hemorrhage results from an increase in alveolar transmural pressure due to a more negative pleural pressure and higher pulmonary capillary pressure during exercise, lack of collateral alveolar ventilation ,and small airway obstruction .Furosemide induced reductions in pulmonary artery pressure and pulmonary artery wedge pressure in horse could decrease lung fluid volume and work of ventilation ,thereby, tendency of epistaxis decreases. Effect of furosemide on left arterial pressure or pulmonary artery wedge pressure in horses during exercise has not been reported.

Furosemide a diuretic that’s been used since the early 1970’s to prevent or diminish EIPH severity in race horses

Furosemide does not affect hemostatic mechanism measured in blood collected after maximal exercise in trained standardbred horses, nor in blood collecting during mild submaximal exercise in untrained standardbred horses. Theoretically, if horses are given furosemide, drug draws water away from lungs and keep the blood pressure from getting too high, thus preventing gaps in vessels and the blood from getting into lungs.

Administration of furosemide in race horses:

EIPH plagues many racehorses, with up to 75% of thoroughbreds affected by this condition. This medication does not actually cure EIPH, it actually reduces EIPH ‘’scores’’ which means affected horses bleed less during exercise when they receive furosemide .Timing of furosemide administration greatly impacts efficacy of furosemide and therefore athletic performance .It can be administered 4 hours prior to race or 24 hours prior to race but 4 hours prior were more effective than 24 hours . Faster horses are affected more than slower ones.