ANTAGONISM OF VECURONIUM AND ATRACURIUM: COMPARISON OF NEOSTIGMINE AND EDROPHONIUM ADMINISTERED AT 5% TWITCH HEIGHT RECOVERY

In 39 healthy patients antagonism, by neostig-mine 0.07 mg kg^–1or edrophonium 0.8 mg kg^–1, of neuromuscular blockadeinduced by vecuronium or atracurium, was compared. Reversalwas attempted when the height of the single twitch (TH) hadrecovered spontaneously to 5% of the control value. The evokedresponses, initially single twitch, then train-of-four (TOF)were observed until the TOF ratio was 70%. Induced recoveryfrom TH 5% to 25% was shorter following edrophonium than followingneostigmine with both vecuronium (P < 0.05) and atracurium(P < 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 shorterfollowing neostigmine than following edrophonium with both vecuronium(P < 0.01) and atracurium (P < 0.01). Edrophonium hada much more variable effect on vecuronium than on atracurium.These results show that although the onset of action of edrophoniumwas faster than that of neostigmine, this did not lead to afaster clinical recovery, and antagonism by edrophonium maybe delayed in a number of patients if vecuronium is the neuromuscularblocker.