Plasma dopamine concentrations following dopamine infusion to isoflurane-anesthetized New Zealand White rabbits

Abstract

ObjectiveTo determine the pharmacokinetics of dopamine following a short infusion in isoflurane-anesthetized rabbits. Study designProspective, descriptive pharmacokinetic study. AnimalsA group of six adult female New Zealand White rabbits weighing 4.4 ± 0.2 kg. MethodsRabbits were anesthetized with isoflurane in oxygen and maintained at 1.2 × minimum alveolar concentration of isoflurane (2.3% atmosphere). Dopamine (30 μg kg–1 minute–1) was infused for 10 minutes. Arterial blood was sampled prior, during and following the infusion at various intervals for 1 hour. ResultsA one-compartment model with baseline concentration best fitted the time–plasma dopamine concentration data. Estimated typical population value (interindividual variability) for volume of distribution and clearance were 10.3 (232%) L kg–1 and 9.9 (508%) L minute–1 kg–1, respectively. Conclusions and clinical relevanceThere was a large degree of interindividual variation in the disposition of dopamine. The large volume of distribution and high metabolic clearance rate reported for dopamine in this study likely explains the lack of clinical efficacy of dopamine in rabbits at doses up to 30 μg kg–1 minute–1.