Scientists: Variability in Clenbuterol Makes Regulation Tough
Scientific advisors discussed concerns about clenbuterol regulation at the most recent National Horsemen's Benevolent and Protective Association convention. The challenge, they said, besides the difference in withdrawal times between states, is that horses metabolize the drug at drastically different rates, with traces detectable at 14 days in some individuals, and as much as 30 days in others. In still other horses, the drug is undetectable after three days post-administration.
Clenbuterol is used as a bronchodilator for horses with respiratory infections. Further, Dr. Steven Barker, chemist for the Louisiana State Racing Commission, is skeptical of the Racing Medication Testing Consortium proposed 14-day cutoff for administration. He's even more skeptical that the group won't release its documents backing the scientific basis for the withdrawal time without a non-disclosure agreement.
“Good scientists would not want to keep good information secret,” Barker told Blood-Horse. “It's not a scientific document, it's a political document–that's shocking.”
Others say that there may be spikes in the amount of the drug in horses' systems at ten days; still others say the affects of the drug is more pronounced in Quarter Horses than Thoroughbreds at large doses.
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