Caffeine and Theobromine Identifications in Post- Race Urines: Threshold Levels and Regulatory Significance of Such Identifications

Caffeine is a widespread environmental substance, and testing for caffeine is now highly sensitive. Currently, many authorities in North America are not concerned about plasma caffeine concentrations of 100 ng/ml, equivalent to 300 ng/ml in urine. This is because such low caffeine concentrations are likely to be associated with environmental exposure to caffeine and are also unlikely to be associated with pharmacological responses. Authors’ addresses: Graduate Center for Toxicology, Health Sciences Research Building, University of Kentucky, Lexington, KY 40536 (Budhraja); Maxwell Gluck Equine Research Center, Farm Lane and Nicholasville Road, University of Kentucky, Lexington, KY 40546 (Camargo, Hughes, Tobin); U.K. Livestock Disease Diagnostic Center, 1490 Bull Lea Road, Lexington, KY 40512 (Lehner); Florida Horsemen’s Benevolent and Protective Association, PO Box 1808 Calder race course, Opa-Locka, FL 33056 (Stirling); and Connolly’s Redmills, Goresbridge, Kilkenny, Ireland (Brennan, Dowling); e-mail: [email protected] (Tobin). © 2007 AAEP. *Presenting author.