title: Antagonism of pancuronium and its metabolites by neostigmine in cats.
abstract: Antagonism by neostigmine of neuromuscular blockade produced by pancuronium or its metabolites was studied in the cat anterior or tibialis muscle-peroneal nerve preparation using constant infusions of muscle relaxants. The ED50 of neostigmine (dose which caused a 50% antagonism) was 16, 11, 29, and 26 micrograms/kg for pancuronium, 3-hydroxypancuronium, 17-hydroxypancuronium, and 3, 17-hydroxypancuronium, respectively. Times of onset of neostigmine action were shorter when antagonizing 17-hydroxypancuronium neuromuscular blockade. Duration of neostigmine action when antagonizing 17- or 3, 17-hydroxypancuronium blockade was shorter than with pancuronium or 3-hydroxypancuronium. We conclude that more neostigmine is required to antagonize 17- or 3,17-hydroxypancuronium neuromuscular blockade than is required to antagonize pancuronium. Conversely, less neostigmine was required to antagonize 3-hydroxypancuronium blockade.
mesh_terms: D000818:Animals; D002415:Cats; D004305:Dose-Response Relationship, Drug; D009388:Neostigmine / Q000008:administration & dosage / Q000494:pharmacology*; D010197:Pancuronium / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013997:Time Factors
chemical_list: D009388:Neostigmine; D010197:Pancuronium