Concentrations of caffeine, theophylline and theobromine in plasma and urine of dogs after application of coffee, tea and chocolate and its relevance to doping

The methylxanthines caffeine, theophylline and theobromine are frequently detected in doping samples of racing greyhounds leading to the disqualification of the animal and possibly further penalties of the owner. The present study demonstrates that after application of coffee and tea to dogs caffeine, theophylline and theobromine can be found in plasma and urine. After feeding of cocoa products (chocolate) theobromine was the predominant methylxanthine to be analysed. Therefore the quantitative relationship of the various methylxanthine metabolites detected can indicate the origin of the ingested methylxanthines. In order to avoid violation of doping regulations, dog owners should assure that their anima Is have no access to methylxanthine-containing diets in the days before racing com petitions. Furthermore the results indicate, that by the uptake of products which are rich in theobromine such as cocoa powder or cooking chocolate toxic to lethal plasma concentrations of this methylxanthine can be attained.