Pharmacokinetics of Rocuronium in Children Aged 4???11 Years

Abstract

Comment This investigation used two population-based pharmacokinetic analysis methods, mixed-effects modeling and naive pooled data analysis, to determine the pharmacokinetic variables for rocuronium. Rather than the two-stage approach, which uses frequent blood sampling, calculation of kinetic variables for each subject, and calculations of mean values, these methodologies analyze data from all subjects simultaneously to determine population kinetic values. Population methods have an advantage in that fewer samples (four samples per subject in this study) are required, which is advantageous for pediatric studies. The major finding was that rocuronium clearance was weight- (and presumably age-) dependent. Although absolute clearance increased with age, weight-normalized clearance was greater in children than adults and greatest in the smallest children. Thus, rocuronium elimination was fastest in the smallest children. Assuming rocuronium pharmacodynamics parallel the kinetics, recovery would also be fastest in the smallest children. Although not tested, these results suggest that higher doses of rocuronium may be used in smaller children, with the potential benefit of faster onset, without prolonging duration of effect compared with older children or adults. This hypothesis, however, remains to be tested.