On July 13 scientific and regulatory advisers to the National Horsemen’s Benevolent and Protective Association (HBPA) expressed concerns over the proposed withdrawal time and testing level for the bronchodilator clenbuterol, and they warned horsemen of potential pitfalls should the regulations be adopted.

Clenbuterol was the topic of a medication forum that was part of the National HBPA summer convention in Shakopee, Minn. The drug, considered therapeutic, has been subject to different administration times and testing levels depending on the jurisdiction, thus the effort by the Racing Medication and Testing Consortium (RMTC) and Association of Racing Commissioners International to push for uniform guidelines.

Steven Barker, MS, PhD, chemist for the Louisiana State Racing Commission, said the proposed 14-day cutoff for administration, threshold of 140 picograms per milliliter in urine, and "limit of detection" in plasma are potential minefields for horsemen. Barker said scientific research has shown clenbuterol can be detected at 14 days—even 30 days in some cases—in horses, or not be detected within three days of administration in other horses.

"There is a lot of variability in the levels being seen," Barker said. "Is this a defacto ban on clenbuterol? I’d be scared to hell to use it