“Weak” support for use of furosemide in racehorses

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A panel of experts has strongly recommended that exercise-induced pulmonary hemorrhage be considered a disease. The experts also gave a “weak” recommendation for use of furosemide in management of racehorses with EIPH. These findings result from a petition by the American Association of Equine Practitioners in 2013 for the American College of Veterinary Internal Medicine to develop a consensus statement on EIPH.

ACVIM logoThe condition occurs in most Thoroughbred and Standardbred racehorses and in many other horses subjected to strenuous exercise. Furosemide is given to U.S. racehorses on therapeutic grounds to reduce the risk of bleeding into the lungs, but opponents of its use believe a key motivation is the lift in performance seen in horses administered the powerful diuretic.

The seven-member panel assessed evidentiary reports in the peer-reviewed literature to determine the following:

  • Whether EIPH adversely affects horse health, welfare, or both.
  • Whether EIPH affects the athletic capacity of horses.
  • The efficacy of prophylactic interventions with EIPH.
  • Whether furosemide affects the athletic capacity of horses.

What the panel found was, first, that much of the evidence was of low to very low quality and that experimental studies frequently lacked adequate statistical power.

Second, the experts concluded that there was moderate-to-high quality evidence that EIPH is progressive, is associated with lung lesions, adversely affects racing performance, and when severe, is associated with a shorter career duration.

Finally, they decided that furosemide is effective in decreasing the incidence and severity of EIPH and that administration of furosemide is, essentially, performance-enhancing. Specifically, they found that there was moderate-quality evidence that furosemide given intravenously four hours before racing was associated with improved racing outcomes in Thoroughbreds and Standardbreds.

Ultimately, the recommendation for use of furosemide in management of racehorses with EIPH is weak “because the panel recognizes that conditions for use of furosemide in some horses, such as racehorses, is regulated by racing jurisdictions that must consider a broad range of factors (not just efficacy) and that there continues to be extensive discussion among these stakeholders regarding policies and perceived need for furosemide prophylaxis,” according to the consensus paper.

The panel didn’t make a recommendation regarding other drug interventions for the prevention of EIPH because of the absence of studies or the low quality of evidence. The experts also noted that they purposely did not address regulatory issues such as detection of drug administration or the potential masking effect of furosemide on other medications or substances and did not address the pathophysiology of EIPH, risk factors for the condition, or the effect of allowing the use of furosemide on the health or racing career of horses.

The entire findings, published in the May/June issue of the Journal of Veterinary Internal Medicine, are available here.

The AVMA, for its part, has a policy “Use of Therapeutic Medications in Racehorses,” which endorses the AAEP policy supporting the use of furosemide on race day for the treatment and prevention of EIPH.

Related JAVMA content:

Horse racing model rules see gradual adoption (Feb. 15, 2015)

Uniform horse-racing rules gaining momentum (Feb. 15, 2014)

Furosemide debate continues (Feb. 15, 2014)

Horse racing eyes changes to stay relevant (Nov. 1, 2011)