Effect of different anesthetics on the pharmacokinetics and pharmacodynamics of pancuronium in the cat.

To investigate the effect of different anesthetics on the pharmacokinetics and pharmacodynamics of pancuronium, 120 microgram/kg i.v., cats were anesthetized with either pentobarbital (N = 4), ketamine (N = 4), enflurane (N = 5), or halothane (N = 5). A longer onset time and duration of neuromuscular blockade occurred during enflurane and halothane anesthesia. The apparent elimination half-life was longer and the total voluem of distribution at steady state larger during halothane anesthesia. The plasma concentration of pancuronium required for neuromuscular blockades was less during enflurane than during the other three anesthetics. We conclude that inhalation anesthetics may prolong a neuromuscular blockade by altering both the pharmacokinetics and pharmacodynamics of pancuronium.