title: Importance of early blood sampling on vecuronium pharmacokinetic and pharmacodynamic parameters.
abstract: The effect of early blood sampling on the description of the vecuronium pharmacokinetic-pharmacodynamic relationship was studied following a bolus injection. Sample collection every 10 sec during the first 2 min showed a high concentration peak at 30 to 40 sec, accounting for an important proportion of the total area under the plasma concentration-time curve (AUC). Neglecting it, using only blood samples drawn at 1 and 2 min (limited sampling), led to a significant overestimation of noncompartmentally derived values of mean residence time, clearance, volume of distribution at steady-state and rate of transfer of vecuronium into the effect compartment. Compartmental pharmacokinetics could not be applied to concentration-time curves constructed with early samples, but limited sampling data were fitted to a 2-compartment model. Derived compartmental pharmacokinetic and pharmacokinetic-pharmacodynamic parameters were similar to those obtained noncompartmentally with complete sampling every 10 sec, because back-extrapolation to time zero contributed to the increase in the AUC. However, compartmental analysis does not provide an accurate description of concentration changes following injection.
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Québec, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Ducharme
authors.forename: F
authors.initials: F
authors.lastname: Varin
authors.forename: D R
authors.initials: DR
authors.lastname: Bevan
authors.forename: F
authors.initials: F
authors.lastname: Donati
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014673:Vecuronium Bromide / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology
chemical_list: D014673:Vecuronium Bromide