Priming with anti-cholinesterases--the effect of different combinations of anti-cholinesterases and different priming intervals.

This study was designed to investigate the effect of different combinations of neostigmine and edrophonium when administered in divided doses and the effect of different intervals (priming intervals) between the doses. Seventy-two patients divided into 12 groups (n = 6 in each) were included in the study. An initial dose of neostigmine 0.012 mg.kg-1 or edrophonium 0.2 mg.kg-1 was administered, followed at different priming intervals (1, 2 or 3 min) by either edrophonium 0.8 mg.kg-1 or neostigmine 0.048 mg.kg-1 for antagonism of atracurium-induced neuromuscular blockade. Reversal was attempted at 10 per cent spontaneous recovery of twitch height. Adequate reversal of neuromuscular block (train-of-four ratio of 0.75) was achieved in all patients. Significant (p less than 0.05) acceleration of the recovery index (time taken for the twitch height to recover from 25 to 75 per cent of control) and reversal time (time taken from the end of injection of the priming dose until TOF ratio value had reached 0.75) was obtained in groups which received edrophonium-edrophonium combination. Recovery indices and reversal times were found to be significantly shorter (p less than 0.05) with a 1 min priming interval. In two additional groups of patients premedicated and anaesthetized as the others equipotent mixtures of the antagonists were administered as a single bolus dose. Reversal times were significantly longer (p less than 0.05) when compared to those given the same amounts of the combination but in divided doses with a 1 min priming interval.(ABSTRACT TRUNCATED AT 250 WORDS)