Antagonism of vecuronium and atracurium: comparison of neostigmine and edrophonium administered at 5% twitch height recovery.

In 39 healthy patients antagonism, by neostigmine 0.07 mg kg-1 or edrophonium 0.8 mg kg-1, of neuromuscular blockade induced by vecuronium or atracurium, was compared. Reversal was attempted when the height of the single twitch (TH) had recovered spontaneously to 5% of the control value. The evoked responses, initially single twitch, then train-of-four (TOF) were observed until the TOF ratio was 70%. Induced recovery from TH 5% to 25% was shorter following edrophonium than following neostigmine with both vecuronium (P less than 0.05) and atracurium (P less than 0.05). The recovery indices and times until TH was 75% of control and until the TOF ratio was 70% were not different. The time from a TH of 75% to a TOF ratio of 70% was shorter following neostigmine than following edrophonium with both vecuronium (P less than 0.01) and atracurium (P less than 0.01). Edrophonium had a much more variable effect on vecuronium than on atracurium. These results show that although the onset of action of edrophonium was faster than that of neostigmine, this did not lead to a faster clinical recovery, and antagonism by edrophonium may be delayed in a number of patients if vecuronium is the neuromuscular blocker.