Pypendop Bruno H, Ilkiw Jan E
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.
Am J Vet Res. 2014 May;75(5):441-5. doi: 10.2460/ajvr.75.5.441.
To characterize the pharmacokinetics of dexmedetomidine after IV administration of a bolus to conscious healthy cats.
5 healthy adult spayed female cats.
Dexmedetomidine was administered IV as a bolus at 3 doses (5, 20, or 50 μg/kg) on separate days in a random order. Blood samples were collected immediately before and at various times for 8 hours after drug administration. Plasma dexmedetomidine concentrations were determined with liquid chromatography-mass spectrometry. Compartment models were fitted to the concentration-time data by means of nonlinear regression.
A 2-compartment model best fit the concentration-time data after administration of 5 μg/kg, whereas a 3-compartment model best fit the data after administration of 20 and 50 μg/kg. The median volume of distribution at steady-state and terminal half-life were 371 mL/kg (range, 266 to 435 mL/kg) and 31.8 minutes (range, 30.3 to 39.7 minutes), respectively, after administration of 5 μg/kg; 545 mL/kg (range, 445 to 998 mL/kg) and 56.3 minutes (range, 39.3 to 68.9 minutes), respectively, after administration of 20 μg/kg; and 750 mL/kg (range, 514 to 938 mL/kg) and 75.3 minutes (range, 52.2 to 223.3 minutes), respectively, after administration of 50 μg/kg.
The pharmacokinetics of dexmedetomidine was characterized by a small volume of distribution and moderate clearance and had minimal dose dependence within the range of doses evaluated. These data will help clinicians design dosing regimens once effective plasma concentrations are established.
描述在清醒健康猫静脉注射一剂右美托咪定后的药代动力学特征。
5只健康成年去势雌性猫。
在不同日期以随机顺序静脉注射3种剂量（5、20或50μg/kg）的右美托咪定。给药前及给药后8小时内的不同时间点采集血样。采用液相色谱-质谱法测定血浆右美托咪定浓度。通过非线性回归将房室模型拟合到浓度-时间数据。
5μg/kg给药后，二房室模型最能拟合浓度-时间数据，而20和50μg/kg给药后，三房室模型最能拟合数据。5μg/kg给药后，稳态分布容积中位数和终末半衰期分别为371 mL/kg（范围266至435 mL/kg）和31.8分钟（范围30.3至39.7分钟）；20μg/kg给药后分别为545 mL/kg（范围445至998 mL/kg）和56.3分钟（范围39.3至68.9分钟）；50μg/kg给药后分别为750 mL/kg（范围514至938 mL/kg）和75.3分钟（范围52.2至223.3分钟）。
右美托咪定的药代动力学特征为分布容积小、清除率中等，在所评估的剂量范围内剂量依赖性最小。一旦确定有效血浆浓度，这些数据将有助于临床医生设计给药方案。
