Bute Not in Racing's Best Interest - By Dr. Rick Arthur

 (Originally published in the Sept 18, 2010 issue of The Blood-Horse magazine. Feel free to share your own thoughts and opinions at the bottom of the column.)  

Earlier this year the Racing Medication and Testing Consortium recommended the phenylbutazone blood level allowed in racehorses be dropped to 2 micrograms per milliliter. Phenylbutazone is a potent non-steroidal anti-inflammatory drug (NSAID) prohibited under international rules but allowed in the United States.

Phenylbutazone (Bute) and flunixin (Banamine) are NSAIDs commonly used in horses; ibuprofen (Advil) and acetaminophen (Tylenol) are their human equivalents. All these drugs have analgesic (pain-killing) activity. Phenylbutazone is seldom prescribed in humans because of its serious side effects. 

Horses can’t talk. They can’t tell us their right ankle is hurting or that they hurt anywhere else. We can only determine if our horses have a problem by the signs they show such as lameness, heat, swelling, or other clinical indications of a problem. What do NSAIDs do? They hide pain and reduce inflammation. Both of these are important signs for anyone caring for horses.  

I was a racetrack veterinarian for 30 years. The first thing I would do when I was asked to examine a horse was to inquire whether the horse was on Bute or other medication. I did so because many drugs, and especially Bute, interfere with a veterinarian’s ability to do a meaningful clinical examination.

This masking of clinical signs doesn’t apply to veterinarians alone. The jockey and trainer are in the same predicament. The horse feels fine to the jockey and looks fine to the trainer, whether the horse is fine or not. Dr. Tom Brokken, a well-respected racetrack practitioner from Florida and a member of the RMTC’s scientific advisory committee, believes the use of phenylbutazone is a bigger problem in training than it is in racing because trainers cannot get an accurate assessment of the soundness of their horses.

A key safety check in our system is the pre-race examination of horses by our track and state veterinarians. Pre-race examinations can be challenging. There are too many horses, too few veterinarians, and not enough time. After several years of discussion and consideration, the Association of Racing Commissioners International’s regulatory veterinarian committee publicly expressed concern to both the RMTC and ARCI that current phenylbutazone threshold levels compromise the pre-race veterinary soundness evaluation.

Dr. Larry Soma, from the University of Pennsylvania and a member of the RMTC scientific advisory committee, volunteered to review the scientific literature on phenylbutazone; all members of the committee had opportunity for input.

The bottom line of Dr. Soma’s review: the regulatory veterinarians’ concerns were justified. The preponderance of scientific evidence indicates phenylbutazone at levels currently permitted in U.S horse racing compromises clinical evaluation. Dr. Soma’s review is available on the RMTC website (www.rmtcnet.com).

In fact, an honest analysis of the published literature suggests if horse racing is to completely eliminate the problem of phenylbutazone masking injury, U.S. racing would need to adopt a minimum 48-hour withdrawal time for blood testing or the long-standing international rule based on urine testing. Until such time as the drug-testing laboratories in this country can improve sensitivity for cortisone drugs, the RMTC scientific advisory committee believes the 2ug/ml level for phenylbutazone is the best option today for U.S. racing.

California has had an extensive necropsy program for 20 years. All horses dying within a CHRB racing enclosure are necropsied (autopsied) by pathologists associated with the UC-Davis School of Veterinary Medicine. What is clear, and has been clear for some time, is that 90% of all horses suffering fatal musculoskeletal injuries have pre-existing pathology at the site of the fatal injury. Why are our examining veterinarians missing these pre-existing injuries? For that matter, why are the trainers?

The veterinary professionals we task with the final safety check for our sport tell us they can’t do their jobs to the best of their ability with current regulations. This isn’t just about horses. Most jockey injuries are collateral damage from catastrophic racing injuries suffered by horses.

In the final analysis, this issue is about pain-killing drugs, horse fatalities, and injured jockeys. We need to do what is best for our horses, our jockeys, our fans, and our sport. Treating horses with pain killers before they are examined or compete is not in the best interests of any of those groups.

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