Medication panel recommends limit on clenbuterol use

A widely funded racing group studying medication use has recommended that states adopt regulations that would require the 14-day withdrawal of clenbuterol, the popular bronchial dilator that can be used to build muscle mass when used regularly.

The Racing Medication and Testing Consortium approved the 14-day withdrawal guideline for clenbuterol along with recommendations for withdrawal times for five other drugs. The consortium, which is funded by a wide cross section of the industry, had funded studies examining the elimination of the six drugs in an effort to determine the levels of the drugs that should be allowed to appear in postrace urine and blood samples.

The 14-day guideline for clenbuterol would require many states to adopt new regulations for the drug. Many states currently recommend a withdrawal of four days, though some states have recently adopted longer withdrawal times. One month ago, New York passed a 21-day withdrawal for clenbuterol, citing a report studying a spate of breakdowns at Aqueduct earlier this year that said many trainers and veterinarians were administering the drug daily.

Dr. Dionne Benson, the medication consortium’s executive director, said that the withdrawal time for clenbuterol was based on the lower end of a therapeutic dose of the only veterinary product containing the drug that is approved for use in horses. As a result, the new withdrawal time will largely prevent horsemen and veterinarians from using the drug chronically to take advantage of its muscle-building properties, at least within two weeks of a race.

The other withdrawal times recommended by the consortium include a 48-hour guideline for acepromazine, the tranquilizer; a 72-hour guideline for mepivacaine, an anesthetic; a 48-hour guideline for butorphanol, an analgesic; a 48-hour guideline for dantrolene, a muscle relaxant; and a 48-hour guideline for detomidine, a sedative and analgesic.

With the studies examining withdrawal times complete, the medication panel will now focus its research budget on detection methods for illegal drugs, the consortium’s chairman, Dr. Rick Arthur, said. Arthur is also the equine medical director for the California Horse Racing Board.