Furosemide’s use in racehorses to avoid exercise induced pulmonary haemorrhage (EIPH) Dr. Aisha Javed1, Dr. Muhammad Amjad2

Furosemide’s use in racehorses to avoid exercise induced pulmonary haemorrhage (EIPH)

Dr. Aisha Javed1, Dr. Muhammad Amjad2

Writer details:

1.Dr. Aisha Javed, Faculty of Veterinary and Animal Sciences, University of Agriculture Faisalabad.

2.Dr. Muhammad Amjad, Veterinary officer Wildlife Park Gatwala Faisalabad, Punjab Wildlife and Parks Department.

Introduction :

Furosemide a diuretic has been used empirically and has been used legally approved for many years by US racing industry to control exercise induced pulmonary haemorrhage or bleeding.Its use in horses for this purpose is highly controversial and has been criticized by organization outside and inside of racing industry.

History of Furosemide use :

Furosemide has been used since early 1970’s in an attempt to prevent or lessen EIPH severity in race horses.

History of EIPH (exercise induced pulmonary haemorrhage):

EIPH was first recorded in literature in late 1700’s when it was identified as epistaxis after intense exercise and decrease in perfomance.Fiberoptic endoscope was invented in 1970’s and veternarians found that there was evidence of bleeding in the trachea of upto 80% of racehorses after race.Afterwards, bronchoalveolar lavage showed evidence of bleeding at alveolar capillary level which was later known as EIPH.

Applied pharmacology of Furosemide to avoid Exercise induced pulmonary haemorrhage (EIPH):

Furosemide is the most commonly used drug to prevent EIPH despite the lack of a clear rationale for its use .Pulmonary haemorrhage occurs due to;                                                                                                         (1) An increase in alveolar transmural pressure resulting from more negative pleural pressure.   (2) Higher pulmonary capillary pressure during exercise.                                                                                                 (3) Lack of collateral alveolar ventilation.                                                                                                              (4) Small airway obstruction.

In horse Furosemide induced reductions in pulmonary artery pressure and pulmonary artery wedge pressure could decrease lung fluid volume and work of ventilation ,as aresult of which , tendency of epistaxis diminishes. In horses during exercise effect of Furosemide on left artrial pressure or pulmonary artery wedge pressure has not been reported.

                Furosemide does not affect hemostatic mechanism measured neither in blood collected after maximal exercise in trained thoroughbred horses,nor in blood collected during mild submaximal exercise in untrained thoroughbred horses.Theoretically,Furosemide draws water away from lungs and keeps the blood pressure from getting too high, which ultimately prevent gaps in vessels and the blood from getting into lungs.

Administration of Furosemide in race-horses:

EIPH plagues many racehorses,Upto 75% of thoroughbreds are affected by this condition.Furosemide does not actually cure EIPH,but it infact,reduces EIPH ‘’scores’’ which means that affected horses bleed less during exercise when Furosemide is administered to them.Timing of Furosemide administration highly impacts its efficacy and thus athletic performance .It can be administered 4hrs or 24 hrs prior to race,but 4 hrs prior is more effective than 24 hr.Faster horses are affected more than slower horses