Pharmacokinetics of xylazine in ponies: influence of yohimbine.
Twenty healthy ponies were given i.v. 1.1 mg/kg of xylazine from 2 manufacturers and the pharmacokinetic parameters calculated from the disposition curves. The disposition curves for the 2 commercial preparations were not different. Yohimbine, an antagonist of the pharmacologic effects produced by xylazine, did not alter the disposition of xylazine in the plasma. A single i.v. bolus of xylazine was completely described in 17 of 20 animals by the biexponential equation: Cp = 1.30e(-0.3955t) + 0.58e(-0.033t) where Cp represents the concentration of xylazine in the plasma at time t (min). The t1/2 beta was 75 +/- 13 min and whole body clearance was 18.9 +/- 1.5 (ml/min.kg).
Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine, Iowa State University, Ames 50011.
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Dyer
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Hsu
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Lloyd
D000818:Animals; D004347:Drug Interactions; D005260:Female; D006736:Horses / Q000378:metabolism*; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D013843:Thiazines / Q000493:pharmacokinetics*; D014991:Xylazine / Q000493:pharmacokinetics*; D015016:Yohimbine / Q000494:pharmacology*
D013843:Thiazines; D014991:Xylazine; D015016:Yohimbine