Pharmacokinetics of cisatracurium in children of different ages

Objective To study the pharmacokinetics of cisatracurium in children of different ages.Methods Twenty-four ASA Ⅰ or Ⅱ children undergoing elective surgery were divided into 2 age groups:group A ＜2 yr and group B ≥2 yr - ＜ 5 yr.Arterial blood samples were obtained at 2,4,6,8,10,15,20,30,45,60,90,120 min after a bolus dose of cisatracurium (0.15 mg/kg).Plasma concentrations (Cp) of cisatracurium were measured by high performance liquid chromatography.The data obtained were analyzed by 3P97 pharmacokinetic software.Distribution half-life( t1/2α ),elimination half life( t1/2β ),A,B,distribution rate constant ( α ),elimination rate constant (/β),central volume of distribution (Vc),total clearance (CL) and apparent volume of distribution (Vd),K1o,K12,K21 were recorded.Results The Cp versus time curve for cisatracurium was fitted to a two compartment pharmacokinetic model.There were no significant differences in t1/2α,t1/2β,A,B,a,β,K10,K12,K21 between the 2 groups.Group A had a significantly larger Vc,CL and Vd than group B.Conclusion The Cp versus time curve for cisatracurium is best described by a two-compartment pharmacokinetic model.Vc,CL and Vd are significantly larger in children under the age of 2- than in children between 2 and 5. Key words: Neuromuscular nondepolarizing agents; Child; Pharmacokinetics