NEUROMUSCULAR EFFECTS OF ROCURONIUM IN PATIENTS RECEIVING BETA-ADRENOCEPTOR BLOCKING, CALCIUM-ENTRY BLOCKING AND ANTICONVULSANT DRUGS

We have studied the onset and duration of action of rocuronium 0.6 mg kg(-1) in patients receiving therapy for more than 1 month with beta-r eceptor blacking drugs (n = 16), calcium entry blocking drugs (n = 17) or anticonvulsant drugs (n = 14) and compared these data with those f rom a control group (n = 27), Anaesthesia comprised fentanyl, propofol infusion and nitrous oxide in oxygen. Neuromuscular block was monitor ed by measuring the force of contraction of the adductor pollicis musc le in response to train-or-four (TOF) stimulation. There were no signi ficant differences in onset times between the four groups (mean 62-76 s). Mean times to 25% recovery of T1 (first response in the TOF) and o f the TOF ratio of 0.7 were (38 SD 15) and 58 (22) min, 36 (8) and 61 (19) min, 40 (11) and 68 (22) min, and 25 (61 and 35 (9) min in the co ntrol, beta-blocker, calcium entry blocker and anticonvulsant groups, respectively (P < 0.01 between the anticonvulsant and other groups). W e conclude that chronic therapy with anticonvulsant drugs reduces the duration of action of rocuronium.