Methylxanthine

This chapter presents the traditional categories of overview, etiology/pathophysiology, signalment/history, clinical features, key differential diagnosis, diagnostics, and therapeutics of methylxanthine poisoning in equine. Methylxanthine poisoning occurs in horses that ingest toxic amounts of the methylated xanthine compounds, theobromine or caffeine, present in cocoa or coffee products, respectively. Methylxanthines include theobromine and caffeine, which can be found in cocoa and coffee, and theophylline, which is found in smaller amounts in cocoa/chocolate and tea, and is used medicinally as a bronchodilator. Theobromine and caffeine from coffee husks have been associated with clinical intoxication in horses. Diagnosis of theobromine or caffeine intoxication is established based on a history of ingestion and determination of theobromine or caffeine in feedstuffs, serum, plasma, urine, or stomach contents. The chapter is an indispensable reference for veterinary clinicians and students dealing with equine medicine, as well as for anyone seeking concise and comprehensive information about equine toxicology.