Antagonism of pancuronium- and pipecuronium-induced neuromuscular block

We have compared the antagonism of neuromuscular block produced by pipecuronium with pancuronium in 80 anaesthetized surgical patients using mechanomyography and electromyography. Pancuronium 0.1 mg kg-1 or pipecuronium 0.07 mg kg-1 was given after induction of anaesthesia and neuromuscular block was adjusted to 75% twitch depression at the time of antagonism. The following regimens were used: edrophonium 0.5 and 1.0 mg kg-1, neostigmine 0.04 mg kg-1, pyridostigmine 0.3 mg kg-1 and edrophonium 0.25 mg kg-1 with pyridostigmine 0.15 mg kg-1. Antagonism was evaluated also by the head lift test. There was no difference between the reversibility of neuromuscular block produced by pancuronium or pipecuronium. Edrophonium produced a significantly faster antagonism than neostigmine or pyridostigmine but onset of action was not significantly faster than that of edrophonium with pyridostigmine. All regimens produced 100% (or near 100%) antagonism of twitch response within 15 min. However, TOF fade antagonism was more complete with pyridostigmine, neostigmine and edrophonium 1.0 mg kg-1 than with edrophonium 0.5 mg kg-1. The head lift test indicated somewhat less antagonism with edrophonium 0.5 and 1.0 mg kg-1. Using five monitoring methods, the rank order of reversal potency was: pyridostigmine approximately neostigmineedrophonium 1.0 mg kg-1edrophonium+pyridostigmineedrophonium 0.5 mg kg-1.