Pharmacokinetics of rocuronium bromide (ORG 9426) in patients with normal renal function or patients undergoing...

To determine the effect of end-stage renal disease on the pharmacokinetics of reocuronium bromide (ORG 9426), a new nondepolarizing monoquaternary steroidal neuromuscular blocking drug, the authors administered 600 micrograms/kg rocuronium (2 x ED95) intravenously to ten patients undergoing cadaver renal transplantation and ten healthy patients undergoing elective minor surgery (controls). All patients were anesthetized with nitrous oxide (50-70% in oxygen) and isoflurane (end-tidal concentrations of 1.2 +/- 0.5% and 0.8 +/- 0.2%, mean +/- SD, for control and transplant groups, respectively). Plasma concentrations of rocuronium were determined by capillary gas chromatography. A population-based pharmacokinetic analysis (NONMEM) was used to determine typical values, standard errors, and interindividual variability for the pharmacokinetic parameters and to determine whether these values differed between control and renal transplant patients. Total plasma clearance (2.89 +/- 0.25 ml.kg-1.min-1, mean +/- SE) and volume of the central compartment (76.9 +/- 10.6 ml/kg) did not differ between control and renal transplant patients, whereas volume of distribution at steady state was greater in renal transplant patients (264 +/- 19 ml/kg) than in control patients (207 +/- 14 ml/kg). This resulted in a longer elimination half life in renal transplant patients (97.2 +/- 17.3 min) compared to controls (70.9 +/- 4.7 min). The authors conclude that renal failure and renal transplantation alter the distribution but not the clearance of rocuronium.