CHRB Severely Restricts Use of Clenbuterol

Board approves a 21-day withdrawal period for commonly used bronchodilator May 24.

The bronchodilator clenbuterol, possibly being misused for its anabolic steroid properties, will be severely curtailed for the next year at all California racetracks.

The California Horse Racing Board, meeting at Betfair Hollywood Park May 24, approved a 21-day withdrawal period from the commonly used drug for any horse entered in a race. The move, which becomes effective with the start of the Del Mar summer meet July 18, will be in effect for one year.

The delay in instituting the change will give horsemen a chance to adjust their medication regimen. The previous withdrawal period for clenbuterol was 96 hours.

The board took the unanimous action under its emergency power rule, which allows it to circumvent the full rule-making process that would have required a 45-day public comment period. It could institute a permanent rule change at a later date.

The move follows the success of a similar suspension of clenbuterol use at Los Alamitos Race Course. A rash of positives for excess clenbuterol led regulators to believe that it was being used for muscle building in horses rather than simply to treat breathing problems.

The ban was enacted after CHRB investigators confiscated brands of clenbuterol not approved by the U.S. Food and Drug Administration at Los Alamitos, primarily as a muscle-building agent. Since the suspension of clenbuterol in Quarter Horses was instituted last November, there have been no violations, the CHRB reported.

"The vet bills are lower, the horses are just as healthy, and it hasn't hurt field sizes at all," said Dr. Rick Arthur, the CHRB's equine medical director. "It is also contributing to slower race times."

While there has been no comparable increase in the number of clenbuterol positives in Thoroughbreds, there is no doubt that use of the drug has been widespread, Arthur reported. Blood samples analyzed at the University of California-Davis equine testing facility through its out-of-competition and total carbon dioxide tests found that 53 of 98 horse sampled between March 15-30 had the presence of clenbuterol.

Thoroughbred horsemen are spending from $5 million to $7 million per year to have veterinarians treat their horses with clenbuterol, Arthur told the board.

That indicates that usage is far beyond what would be required to treat only horses with breathing problems, he said after the meeting.

"I think that having more than 50% of horses testing positive for clenbuterol is stretching the limits of credibility," Arthur said.

Arthur added, however, that clenbuterol is a highly effective therapeutic drug for the treatment of small airway disease and should be allowed for horses that need it.

Lou Raffetto, president of the Thoroughbred Owners of California, said horsemen support the suspension of clenbuterol.

“We want to ensure that it’s used for therapeutic purposes but at the same time not have a negative effect on California racing,” Raffetto told the board.

The old rule allowed clenbuterol to appear in post-race tests of Thoroughbreds up to a limit of five nanograms in urine and 25 picograms in blood. Arthur said the new standard would allow trace amounts of clenbuterol that would be in accordance with the three-week withdrawal time. Trainers would face penalties if horses test in excess of those levels.

Dr. Craig Shoemaker, a veterinarian appearing for pharmaceutical manufacturer Boehringer-Ingelheim, urged the board to wait until UC-Davis completes an ongoing study on the effects of clenbuterol before taking action. He said the study is expected to be released within the next 30 days.

Shoemaker said he agreed with the board that non-FDA-approved "bathroom" concoctions of the drug using far greater concentrations than needed "should have no place in racing and we should do everything we can do to make those go away."

But he said the 21-day withdrawal period could lead to trainers running horses "that would be racing in a compromised state."

California is following New Mexico, which instituted a one-year ban on clenbuterol in February.