Open letter from a distinguished equine veterinarian in the US!

Dr. Kellon is a graduate of the very prestigious University of Pennsylvania School of Veterinary Medicine (New Bolton).  

December 6, 2009

 

The shock waves from the FEI's implementation of the progressive medications list has encircled the globe and sharply divided the equine community. I am very concerned by the rhetoric being used to justify the change. I signed the petition at www.no-fei.com, and stand squarely with the BEVA, many of the FEI's own present and past veterinarians, their Honorary Scientific Advisor, all national organizations opposing this change and concerned individuals everywhere.

 

To suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) are not performance enhancing but rather “restorative”, implying they are actually beneficial to the horse, is patently ridiculous and flies in the face of current scientific knowledge. These drugs do not “treat” musculoskeletal issues. They mask the animal's natural, protective pain response by interfering with inflammatory pathways (the cyclooxygenase enzyme systems) while the cause of that pain remains.

 

Short term use of NSAIDs for the humane relief of pain in injured animals is reasonable, but no horse genuinely in need of NSAIDs should be competing. Compelling evidence has accumulated in the human literature that this class of drugs used chronically interferes with the normal metabolism and healing process in bone, joint cartilage and tendon insertion sites onto bone. In fact, human orthopedic surgeons caution their patients to avoid NSAIDs for at least a week before and several weeks after surgical procedures. A review article on the impact of NSAIDs on the musculoskeletal system in humans which appeared in the September 2008 issue of Drugs Today concluded:

 

“It is clear, however, that cyclooxygenase activity is involved in the healing of many skeletal tissues, either directly or indirectly through modulation of the inflammatory response. Consequently, pharmacological manipulation of cyclooxygenase using NSAIDs or celecoxib can profoundly affect skeletal health.”

 

Preliminary studies, published in the American Journal of Veterinary Research in May of 2000 and December of 2001, confirm similar effects in equine tissue. In the study by Dr. Rhode et al, Ohio State, phenylbutazone at 4.4 mg/kg every 12 hours (a common therapeutic dose), significantly reduced mineralization and delayed healing at bone biopsy sites compared to untreated horses. Dr. Beluche et al, also at Ohio State, used the same dosage to assess the effects of phenylbutazone on cartilage and concluded:

 

“Oral administration of phenylbutazone for 14 days significantly decreased proteoglycan synthesis in articular culture explants from healthy horses to a degree similar to that induced by in vitro exposure to IL-1beta [an inflammatory cyotkine in arthritis - EK]. Phenylbutazone should be used judiciously in athletic horses with osteoarthritis, because chronic administration may suppress proteoglycan synthesis and potentiate cartilage damage.”

 

The BEVA has expressed concern that the change could lead to an increase in catastrophic injuries, a concern that is supported by a June 2009 study in the Journal of Veterinary Pharmacology and Therapeutics which found higher levels of phenylbutazone and flunixine in catastrophic breakdowns in racehorses, as well as injuries in general. Pain means injury. Is it not simply common sense that masking pain so that a horse can perform with weakened tissue is asking for trouble?

 

This is to say nothing of the legendary potential for this class of drugs, in particular phenylbutazone, to cause oral ulceration, gastric ulceration, renal damage and right dorsal colitis.

 

It is being claimed that there is no concern over NSAID use in human athletes. In truth, several recent articles have expressed concern over the level of NSAID use by human athletes with respect to decreased blood clotting, drug side effects, negative effects on the ability of muscle to respond normally to exercise, electrolyte abnormalities and the potential for worsening injury, for example:

 

http://sportsmedicine.about.com/od/medicationanddrugs/a/NSAID_endurance.htm

 

We are told that the permitted dosage of 1 gram of phenylbutazone no closer than 12 hours before competition is too low to have a significant effect on lameness and would be administered in a supervised setting. There are several problems with that statement.

 

A study in the December 1994 issue of the Journal of Veterinary Pharmacology and Therapeutics found that 2 mg/kg of phenylbutazone, 1 gram for a 500 kg horse, the same “low” dose being proposed by the FEI, provided as much pain relief as higher doses in an experimental model of severe arthritis. Higher doses only provided a longer duration of pain relief.

 

It's true that a 1 gram dose of phenylbutazone 12 hours out from competition would not be providing significant pain relief at that 12 hour mark. However, the proposed allowable plasma level of 8 µg/mL is well within the known therapeutic blood level and is more consistent with the level that would be found between 6 to 7 hours after administration, not 12. This leaves the door wide open for abuse by anyone inclined to give the horse more drug on their own, a practice called “topping off”. In his letter to the FEI protesting the rule change, Leo B. Jeffcott, former Chair of the FEI Veterinary Committee, refers to past problems with topping off. Does anyone seriously believe that won't happen again?

 

Advocates of the change also refer to violations that occurred under the zero tolerance policy, alluding to those being unjust or the test too sensitive, and applauding the new rules for that reason. However, the level detectable under zero tolerance depends on the sensitivity of the assay being used. These drugs lose their analgesic effects long before the nanogram levels detected by ultrasensitive ELISA tests. Using chromatography techniques, a typical limit of detection for a 3 gram dose of phenylbutazone correlates with the drug having been administered 30 hours prior to testing, or 39 hours for its metabolite, oxyphenylbutazone when testing blood samples. The limit of detection for this high dose when testing urine is 48  hours for the drug itself and 120 hours for its metabolite. Lower doses would be undetectable much sooner. Is it really all that unreasonable to ask that a horse not be given NSAIDs for 3 to 5 days prior to a competition?

 

I am also concerned that the rule change will lead to greater use of NSAIDs in general, both between and at competitions. Trainers and riders will feel that those who are using them are at an advantage and will feel compelled to give their horse an equivalent edge.

 

As a veterinarian and advocate for the horse, I cannot support the progressive drug list and strongly agree with those who feel it is a step backwards both in terms of equine welfare and the clean sport effort.

 

Eleanor M. Kellon, VMD

Equine Nutritional Solutions

Denver, Pennsylvania

USA

www.drkellon.com