Clenbuterol Use Below Expectations in Calif. Sample
by Tracy Gantz
Date Posted: 2/15/2007 6:49:24 PM
Last Updated: 2/16/2007 5:32:41 PM

Only about 12% of horses tested for clenbuterol had measurable levels of the medication in 193 blood samples taken recently, according to Dr. Rick Arthur’s report Thursday to the California Horse Racing Board medication committee.

Arthur, equine medical director for the CHRB, had overseen the tests as part of additional information being provided as the agency mulls possible changes to California’s rule on allowable clenbuterol levels.

The CHRB at its January meeting had sent the clenbuterol issue back to the medication committee for further review. The blood tests were conducted not only to investigate the feasibility of using blood rather than urine tests, but to look into rumors that clenbuterol is administered to most horses racing in California.

“We found very little evidence that clenbuterol is being administered within 48 hours,” Arthur told the committee. “Several of the samples came close to 48 hours, but it doesn't appear to be a problem.”

Arthur said that the blood samples “reasonably matched” the urine samples from the same horses, with some level of clenbuterol showing up in about a third of the urine samples. He said that it is “debatable” whether clenbuterol is being over-used, but that in a normal racetrack situation, about 30% of the horses have small airway disease, the reason many veterinarians prescribe clenbuterol.

“Our analysis indicates about a third of horses show low-level residues of clenbuterol in their system when they're racing,” Arthur said. “Certainly, we aren't seeing 90% as has been rumored.”

Arthur noted that other health concerns have been raised about clenbuterol use. With several unexplained sudden deaths in racehorses recently, Arthur said that clenbuterol will be evaluated in horses from California’s necropsy program to see if there is a relationship.

Arthur and Dr. Scott Stanley, director of the Ken Maddy Laboratory at the University of California at Davis, answered questions from the committee regarding testing for clenbuterol at different withdrawal times. The committee is investigating establishing a blood level of 25 picograms per milliliter for clenbuterol and a 72-hour withdrawal time.

Arthur and Stanley explained that, at the 25-picogram level, horsemen would not get a positive at 72 hours and at 48 hours would get a positive about a third of the time. Arthur felt confident that people would not want to risk administering clenbuterol at 48 hours because of the CHRB’s new penalty guidelines currently under 45-day review.

In response to a question from CHRB Chairman Richard Shapiro, who is also a member of the medication committee, Stanley said that a 25-picogram level would ensure that a horse could receive no performance-enhancing effect from clenbuterol.

He and Arthur told the committee that, if the CHRB wanted to establish a four- or five-day withdrawal time, more research would have to be done because currently the testing doesn’t show appreciable differences between 72, 96, and 120 hours. Stanley explained that, while English jurisdictions recommend withdrawal of five to seven days, theirs is essentially a 72-hour rule with the more conservative withdrawal recommendation to avoid the severe penalties England has in place.

Shapiro said that the CHRB is considering establishing a pharmacy for veterinary medications on racetrack backstretches. He hopes a pharmacy would reduce medication costs for owners and take away any incentive for a person who both prescribes and dispenses medication to over-medicate. Stanley pointed out that such a facility would have to have a licensed pharmacist and that strict federal and state guidelines must be followed.

Ed Halpern of California Thoroughbred Trainers voiced a concern that a pharmacy might change a veterinarian’s current practice of not charging for "office visits" to a trainer’s barn and that such a change could offset any savings from a pharmacy.

Arthur reported on the board proposal on steroids that would treat all steroids except four as Class 3 drugs with Category B penalties. Research will continue into withdrawal times for steroids so that California can comply with any national regulations put into place.

Also during the meeting, Arthur discussed the equine herpesvirus situation at California racetracks. He said that Los Alamitos is the only track that continues to have horses testing positive. However, those horses have been moved off the backstretch into isolation facilities built in the track parking lot. Arthur expected the problem to be eliminated, possibly as early as the weekend.

He urged the CHRB to establish racetrack protocols for future viral outbreaks, as well as plans for disaster preparedness that would include barn fires and earthquakes.

In an advisory issued by the CHRB Feb. 15, the agency announced it will begin out-of-competition testing at state racetracks and authorized training facilities. The primary focus will involve in-depth analysis of specific performance-enhancing drugs. Epoetin and darbepoetin will be specifically targeted in the sample testing, the advisory said.


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