Recovery characteristics following antagonism of atracurium with neostigmine or edrophonium.

The evoked reversal characteristics of atracurium were studied in 21 patients using edrophonium or neostigmine and a train-of-four pattern of stimulation. Reversal of residual atracurium -induced neuromuscular blockade was significantly more rapid using edrophonium compared with neostigmine. The ratio of the fourth twitch in the train-of-four to the first twitch--the T4 ratio--was significantly greater when the first twitch (T1) had recovered to 75% of control T1, using edrophonium compared with neostigmine. A T4 ratio of 0.5 was confirmed to be compatible with the reliable and safe reversal of atracurium -induced neuromuscular blockade.