Horse urine is investigated for metabolites following the oral administration of the large animal analgesic sedative Detomidine to two stallions and intravenous administration of [3H]-Detomidine to a mare. Detomidine carboxylic acid and hydroxydetomidine glucuronic acid conjugate are identified in the urine after the oral doses. About half of the radioactivity of [3H]-Detomidine is excreted in the urine in 12 h after the i.v. dose (80 μg/kg). Most of the excretion occurred between 5 and 12 h in contrast to urine output which is highest 2-5 h after the dosing. The major radioactive metabolite in the urine is Detomidine carboxylic acid. Detomidine carboxylic acid comprises more than two thirds of the total metabolites in all the urine fractions collected[1].
