British journal of anaesthesia
-
The differential sensitivities of A beta, A delta and C fibres of rat vagus nerve to bupivacaine, etidocaine and AL-381 were studied in vitro. In A beta fibres, at 35-37 degrees C, 50 mumole litre-1 of the drugs had similar effects on the action potential amplitude, while at greater concentrations (100 and 200 mumole litre-1) the greatest mean depression of amplitude was seen with etidocaine (n.s.). ⋯ Etidocaine 100 mumole litre-1 was more depressant than the same dose of bupivacaine. The C fibres were blocked most rapidly by AL-381, while etidocaine had the least effect.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Clinical comparison of atracurium and vecuronium (Org NC 45).
The potency, histamine releasing ability, cardiovascular effects, and pharmacodynamics of vecuronium and atracurium were investigated in 64 healthy patients following administration i.v. Cumulative dose-response curves showed vecuronium to be 4.4 times as potent as atracurium. Using the calculated ED90 of each drug (43 micrograms kg-1 for vecuronium and 188 micrograms kg-1 for atracurium), vecuronium had a significantly more rapid onset time and shorter duration of action than atracurium. ⋯ There was no clinical evidence of histamine release during the study. No clinically significant changes in arterial pressure or heart rate were seen after the injection of either drug, although vecuronium caused a statistically significant decrease in heart rate (approximately 5%) at 5 and 10 min after administration. Both drugs would appear to have certain advantages over existing non-depolarizing neuromuscular blocking drugs.
-
Org NC 45, a new non-depolarizing neuromuscular blocking drug, was evaluated in 200 adult patients. The drug was administered in doses of 0.1, 0.15 or 0.2 mg kg-1. ⋯ The duration of clinical relaxation following repeated administration of 2-3 mg was remarkably constant (between 17 and 20 min) thus showing lack of cumulation. The antagonism of residual block was prompt and easy following administration of neostigmine, and the drug lacked any significant cardiovascular effects as seen by routine monitoring.
-
Comparative Study
Neuromuscular and cardiovascular effects of atracurium during nitrous oxide-fentanyl and nitrous oxide-isoflurane anaesthesia.
The neuromuscular and cardiovascular effects of atracurium were compared during nitrous oxide-isoflurane and nitrous oxide-fentanyl anaesthesia in healthy surgical patients. The dose-response curve was shifted significantly to the left during nitrous oxide-isoflurane anaesthesia (ED50 0.068 mg kg-1) as compared with nitrous oxide-fentanyl anaesthesia (ED50 0.083 mg kg-1). For equipotent doses, the time course of neuromuscular effects (onset and duration) was not appreciably different between the nitrous oxide-isoflurane group and the nitrous oxide-fentanyl group. ⋯ The onset time (time from injection to peak effect) for subparalytic doses of atracurium was approximately 6.5 min and is comparable to the onset time for equipotent doses of pancuronium and vecuronium. The duration of neuromuscular effects of atracurium (time from injection to 95% recovery) was approximately 20 min for subparalytic doses and is the same as that of vecuronium and one-third to one-half that of pancuronium. It is concluded that the peak effect of atracurium is enhanced more by nitrous oxide-isoflurane than by nitrous oxide-fentanyl anaesthesia, but for equipotent doses the time-course is the same.