Medication Use in Horse Racing: Yea or Neigh?


Medication use in horse racing has become a hot topic across the country.

Medication use in horse racing has become a hot topic across the country. Uniform standards have been established by the Racing Medication and Testing Consortium (RMTC) for the United States. However, not all states are following these guidelines.1,2 The National Uniform Medication Program consists of medication rules, penalties, and testing guidelines. Additionally, the policy contains the Controlled Therapeutic Substances list, a policy limiting administration of furosemide to third-party veterinarians, a multiple medication violation penalty system, and a laboratory quality assurance program.1

Approved Controlled Therapeutic Medications

The RMTC has established a list of 30 approved controlled therapeutic medications that have use for treating medical conditions in horses, along with withdrawal guidelines to avoid positive tests during races.1 For example, omeprazole may be used to treat or prevent ulcers in horses, and it is recommended to be stopped approximately 24 hours prior to racing.1 It is important to note that administration of more than 1 medication can affect the time for the drug to leave the system, which can cause a positive drug test. Twenty-six states have currently adopted the Controlled Therapeutic Substances List.1 The following medication classes are generally banned from horse racing: anabolic steroids, peptide hormones and growth factors, beta-2 agonists, hormone and metabolic modulators, and certain diuretics.1

The Furosemide Controversy

One controversial medication issue is the use of furosemide (Lasix, Validus) on race day. It is typically administered 4 hours prior to a race to prevent exercise-induced pulmonary hemorrhage (EIPH), which causes bleeding in the lungs and from the nose of horses during strenuous exercise.3,4 Since furosemide reduces plasma volume, it is thought to lower blood pressure in the lungs to prevent bleeding.4 However, there is mixed evidence regarding the efficacy of furosemide for EIPH. In fact, a recent study demonstrated that administration of furosemide both 4 and 24 hours prior to high-speed training did not prevent EIPH.5 The study did show that furosemide reduced the severity of EIPH in those horses affected with this condition.5

The American College of Veterinary Internal Medicine issued a consensus statement that EIPH is considered a disease, and offers a weak recommendation for the use of furosemide for the management of racehorses with EIPH.3 Many questions have been raised as to whether furosemide can be considered performance enhancing, since with fluid loss horses may race faster. Also, diuretics can potentially mask the use of banned drugs. Europe and Australia have banned the use of furosemide on race day due to these concerns.6 There are actually 28 states that allow the use of furosemide on race day, including Kentucky, which is home to one of the most well-known races, the Kentucky Derby, that occurs annually in May.1 Interestingly, California allows conjugated estrogens and furosemide on race day. Conjugated estrogens have not shown a therapeutic benefit for EIPH.

There is currently a federal bill, known as the Horseracing Integrity Act, supported by 64 trainers, that was introduced last year which would establish an agency to monitor medication policy in horse racing and would ban race day furosemide.7 Although there is support for this bill, some opposition remains among the racing industry. The program would consist of the following measures: anti-doping and medication control rules; lists of permitted and prohibited substances; prohibition on the administration of any medication within 24 hours of the race start; and testing and laboratory standards.7

The Bottom Line and Pharmacist Involvement

Based on the available evidence, there may be a place for furosemide in horses with EIPH, but it should not be used in healthy horses for prevention. Many questions regarding the longterm use of furosemide in horses remain to be answered, such as whether it affects the breeding process. There should be federal laws in place for restrictions on medications used in horse racing. The Horseracing Integrity Act could be an important piece of legislation that may assist with establishing federal regulatory standards. Veterinary pharmacists could play an important role in providing drug information education to the horse racing industry on the use of race day medications.


  • Racing Medication and Testing Consortium. The National Uniform Medication Program. Accessed March 31, 2018.
  • Larkin M. Uniform horse-racing rules gaining momentum. J Am Vet Med Assoc. 2014;244(4):386-403.
  • Hinchcliff KW, Couetil LL, Knight PK, et al. Exercise induced pulmonary hemorrhage in horses: American College of Veterinary Internal Medicine consensus statement. J Vet Intern Med. 2015;29:743-758.
  • Equine Health Labs. Lasix and blood viscosity. Accessed April 1, 2018.
  • Knych HK, Wilson WE, Vale A, et al. Effectiveness of furosemide in attenuating exercise-induced pulmonary haemorrhage in horses when administered at 4- and 24-h prior to high-speed training. Equine Vet J. 2017 Sep 30. Doi: 10.1111/evj.12760.
  • European Horserace Scientific Liaison Committee. Control of therapeutic substances in thoroughbred horseracing. Accessed March 31, 2018.
  • Library of Congress. H.R. 2651- Horseracing Integrity Act. Accessed April 1, 2018.

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