PHARMACODYNAMICS OF THE 1R CIS-1'R CIS ISOMER OF ATRACURIUM (51W89) IN HEALTH AND CHRONIC-RENAL-FAILURE

We have studied the pharmacodynamics of the 1R cis-1'R cis isomer of a tracurium (51W89) in 15 healthy subjects and in 17 patients with chron ic renal failure using a bolus dose of 51W89 0.1 mg kg(-1) (2 x ED(95) ). Fifteen patients with normal renal function were investigated also using an approximately equipotent dose of atracurium (0.4 mg kg(-1)). The compound surface action potential of the adductor pollicis muscle, in response to train-of-four stimulation of the ulnar nerve at the wr ist, was recorded until recovery of the height of the first response o f the train-of-four compared with baseline (T1:T0) had reached at leas t 85% and the train-of-four ratio (T4:T1) at least 80%. In the healthy and renal failure patients who received 51W89, there were no signific ant differences in any of the onset or recovery variables except for t he time to 90% depression of T1:T0, which was longer in patients with renal failure (mean 3.7 min vs 2.4 min; P < 0.05). Of the healthy pati ents who were given either 54W89 or atracurium, there were no signific ant differences in the onset data, except for time to maximum block, w hich was longer in the 51W89 group (mean 7.7 min vs 6.2 min; P < 0.01) . The mean times to 10%, 25%, 50% and 75% recovery of T1:T0 and the ti me for T4:T1 > 70% were significantly longer in patients receiving 51W 89. We conclude that 51W89 has an intermediate duration of action whic h was not significantly affected by the presence of chronic renal fail ure. In healthy patients, recovery from 51W89 may take slightly longer than that after atracurium.