HRMC releases recommendations on clenbuterol and betamethasone

Columbus, OH — The Harness Racing Medication Committee released their recommendations on Wednesday (Dec. 5) for the two therapeutic medications, clenbuterol and betamethasone, that were distributed to 16 state racing commissions as well as the Association of Racing Commissioners International for their consideration in establishing medication rules.

The recommendations that were sent with position papers on Wednesday (Nov. 28) identified specific thresholds and withdrawal times for the two medications based upon the advice of the respected veterinarians on the HRMC.

The state agencies that have been sent HRMC recommendations on the two therapeutic medications are: California Horse Racing Board, Delaware Harness Racing Commission, Indiana Horse Racing Commission, Maine State Racing Commission, Maryland Racing Commission, Massachusetts Gaming Commission, Michigan Gaming Control Board, Minnesota Racing Commission, New Jersey Racing Commission, NY State Gaming Commission, Ohio State Racing Commission, Pennsylvania Bureau of Standardbred Horse Racing, Florida Division of Pari-Mutuel Wagering, Illinois Racing Board, Kentucky Horse Racing Commission, and Virginia Racing Commission.

Following are the highlights of  the HRMC’s position on clenbuterol:

Clenbuterol is a β2-adrenoreceptor agonist widely used therapeutically in horses as a bronchodilator.

Clenbuterol is administered to harness horses post-race to aid in clearance of pulmonary secretions and debris inhaled during the course of the race.

The regulatory concern is that clenbuterol, if administered too close to the time of an upcoming race, might enhance performance by reducing normal respiratory secretions occurring during racing, or by improving respiratory function in some other way.


The permissible threshold level should be set at 25pg/mL in plasma for harness horses, with a recommended withdrawal guideline of 96 hours. This is based on the paper (Lehner, et al., 2001) cited in the References section below, where 96 hours after oral administration of 0.08 uk/kg ventipulmin, 5 in 10,000 horses are estimated as being at risk of violating a 30 pg/mL threshold. This dosing schedule/regulatory threshold has a long history of successful application in Kentucky, California, Arizona, Minnesota, New Mexico, Ohio, and Washington (Tobin, et al., 2011, p. 36).

The stated threshold and use guideline are appropriate for horses racing approximately weekly.

The veterinary panel was unanimous in this recommendation.

To read the complete position paper with references on clenbuterol, click here.

Following are the highlights of the HRMC’s position on betamethasone:

Betamethasone is a corticosteroid that acts to prevent release of substances in the body that cause inflammation. It is an approved therapeutic medication in horses administered for the purpose of reducing inflammatory responses from traumatic, oxidative, and allergic sources.

The regulatory concern is that betamethasone could mask injury and therefore place the horse at risk of further injury. Specifically, if betamethasone were administered too close to race time, horsemen and veterinarians would be unable to assess response to treatment before putting the horse at risk by racing.


The permissible plasma threshold should be set at 100pg/mL in plasma for harness horses, with a recommended withdrawal guideline of 6-1/2 days.

Further, for betamethasone acetate and betamethasone sodium phosphate, the permissible threshold level under the industry practice of injecting joints bilaterally should be set at 100 pg/mL in plasma with a recommended withdrawal guideline of 6-1/2 days.

The veterinary panel was unanimous in this recommendation.

To read the complete position paper with references on betamethasone, click here.

The Harness Racing Medication Collaborative, which was created by the USTA Subcommittee on Medication in May 2018, consists of the following veterinarians who have expertise in the Standardbred racehorse: Dr. Marty Allen, Dr. Richard Balmer, Dr. Clara Fenger, Dr. Peter Kanter, Dr. Brian MacNamara, Dr. George Maylin, Dr. Kenneth McKeever, Dr. Andy Roberts, Dr. James Robertson, and Dr. Thomas Tobin.

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