Population pharmacokinetics study of dexmedetomidine in Chinese adult patients during spinal anesthesia

The objectives of this study were to construct a population pharmacokinetics model for dexmedetomidine used in Chinese adult patients with spinal anesthesia and to identify the key factors affecting the pharmacokinetics of dexmedetomidine.

A total of 34 subjects (elderly group: n = 15; young group: n = 19) undergoing spinal anesthesia received dexmedetomidine with a loading dose of 0.5 μg×kg(-1) for 10 minutes, followed by a maintenance dose of 0.5 μg×kg-1×h(-1) for 50 minutes. Blood samples were collected until 10 hours after dosing. Laboratory and respiratory parameters, and dexmedetomidine concentrations were measured. A population pharmacokinetic model for dexmedetomidine was constructed using a nonlinear mixed effects model (NONMEM).

Pharmacokinetics of dexmedetomidine can be described by a three-compartment model. The respective typical values for clearance (CL), V1, V2, Q2, Q3, and V3 were 0.883 L×min(-1), 17.6 L, 51.5 L, 2.37 L×min(-1), 0.517 L×min(-1), and 44.00 L. Alanine aminotransferase (ALT), age, and body weight were key factors affecting CL, V1, and V2, respectively.

A three-compartment model can be used to describe the pharmacokinetics processing of dexmedetomidine for Chinese adult patients during spinal anesthesia. The population pharmacokinetic of dexmedetomidine was generally in line with results from previous studies.