Muscle relaxation with an infusion of vecuronium.

Vecuronium was administered by a continuous intravenous infusion following a bolus dose of 0.1 mg kg-1 in 10 patients. Following recovery of twitch height to 10% of control, steady state dose requirement for maintaining a 90% block was attained in an average of 15.4 min. The average dose required was 0.083 mg kg-1 h-1 or 3.27 mg m-2 h-1. Large individual variations were observed but each patient required an approximately constant dose over periods up to 4.5 h. Recovery was prompt following cessation of infusion.

Plasma cholinesterase levels following pancuronium and vecuronium.

Plasma cholinesterase levels were measured in 52 patients following administration of pancuronium 1 mg/70 kg (10 patients) and 0.1 mg/kg (10 patients) and vecuronium in doses of 1 mg/70 kg (10 patients), 0.1 mg/kg (10 patients) and 0.2 mg/kg (12 patients). Both doses of pancuronium produced a significant (P less than 0.05 - less than 0.005) reduction in the enzyme levels. Vecuronium in a dose of 1 mg/70 kg was without any significant effects but the two higher doses produced a dose-related reduction of about 8 and 16% in the enzyme levels, respectively, which was statistically significant (P less than 0.05 - less than 0.001).

Vecuronium and d-tubocurarine combination: potentiation of effect.

To evaluate possible potentiation of neuromuscular blocking effect of a combination of vecuronium and d-tubocurarine, cumulative dose-response curves were constructed to compare the potency of this combination with vecuronium and d-tubocurarine given alone. Ten patients each were given incremental injections of 80 micrograms/kg d-tubocurarine or 5 micrograms/kg vecuronium plus 40 micrograms/kg d-tubocurarine, the data for incremental administration of 10 micrograms/kg vecuronium being used from our previously published study (7). The results showed the combination of vecuronium plus d-tubocurarine to be significantly more potent (P less than 0.05) than would be expected from a simple additive effect of the individual drugs given alone. The ED95 doses of d-tubocurarine and vecuronium were 530 micrograms/kg and 57 micrograms/kg, respectively, when administered alone, but when administered together, the ED95 doses were 160 and 20 micrograms/kg, respectively.

An evaluation of Org NC 45 (vecuronium) in paediatric anaesthesia.

Vecuronium (Org NC 45) was evaluated as a neuromuscular blocking agent in children and compared with pancuronium in a double-blind study. Satisfactory intubating conditions were present 90 seconds after 0.1 mg/kg of either drug. The onset of complete block was quicker after vecuronium but the greatest difference was found in the duration to 25% recovery which was significantly shorter with vecuronium (20 min) compared with pancuronium (48 min). The use of vecuronium was associated with cardiovascular stability and no clinical evidence of histamine release. Antagonism of the block was readily achieved with neostigmine.

Time course of action of combinations of vecuronium and pancuronium.

Vecuronium 0.1 mg/kg, pancuronium 0.1 mg/kg, vecuronium 0.075 mg/kg + pancuronium 0.025 mg/kg, vecuronium + pancuronium 0.05 mg/kg each and vecuronium 0.025 mg/kg + pancuronium 0.075 mg/kg were compared with respect to time taken to onset of effect, duration of clinical relaxation and intubation conditions in five groups of 20 patients each. The time to onset and intubating conditions were similar in all the groups, indicating that the combinations have no advantage over the individual drugs. The duration of clinical relaxation was 25 minutes with vecuronium, and increased as the proportion of pancuronium in the mixture increased, being 56 minutes with pancuronium 0.1 mg/kg.

Time course of muscle relaxation with a combination of pancuronium and tubocurarine.

A combination of pancuronium and d-tubocurarine is associated with potentiation of the neuromuscular blocking effects of each drug used singly. The time to onset of maximum block and the time to 25% recovery after administration of equipotent (ED95) doses of pancuronium (0.07 mg/kg) alone, d-tubocurarine (0.51 mg/kg) alone, and pancuronium (0.024 mg/kg) in combination with d-tubocurarine (0.144 mg/kg) were studied in three groups of 10 patients each. The time to onset of maximum block was slightly but not significantly shorter with the combination (3.5 min) than with pancuronium (4.78 min) or d-tubocurarine (4.88 min). The time to 25% recovery with the pancuronium-d-tubocurarine combination (39.7 min) was significantly shorter than it was after d-tubocurarine (57.6 min) but not significantly different from pancuronium (54.4 min). The combination of pancuronium and d-tubocurarine also was associated with greater cardiovascular stability.

Clinical evaluation of Org NC 45.

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. Intubation could be satisfactorily carried out at around 90 s in 90% of patients. The duration of clinical relaxation varied from 23 min with 0.1 mg kg-1 and neuroleptanaesthesia to 71 min with 0.2 mg kg-1 and anaesthesia with halothane or enflurane. 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.

Pretreatment with vecuronium as a prophylactic against post-suxamethonium muscle pain. Comparison with other non-depolarizing neuromuscular blocking drugs.

One hundred and ninety-eight patients undergoing minor surgery were assessed for evidence of post-suxamethonium muscle pain on the 1st and 2nd days following surgery. Patients were allocated to nine groups and were given one of four non-depolarizing neuromuscular blocking drugs (vecuronium, gallamine, tubocurarine or pancuronium) 1 or 2 min before the administration of suxamethonium. A control group received an inert medication. Forty-one per cent of patients receiving no pretreatment experienced muscle pain. This frequency was decreased to around 20% following pretreatment. In general, the frequency of pain was less in the groups receiving pretreatment at 1 min, but the difference was not significant. The groups receiving vecuronium before suxamethonium had the lowest overall frequency of pain over the 2 days (19%), although this was not significantly different from other pretreatments.

Haemodynamic effects of vecuronium, pancuronium and atracurium in patients with coronary artery disease.

Thirty patients with ischaemic heart disease scheduled for coronary artery bypass grafting were randomly allocated to three equal groups. Following morphine, hyoscine and pentobarbitone premedication, anaesthesia was induced with diazepam 0.3 mg kg-1. Five minutes later neuromuscular blockade was induced with pancuronium 0.1 mg kg-1, vecuronium 0.1 mg-1 or atracurium 0.5 mg kg-1, followed after 6 min by fentanyl 25 micrograms kg-1. Pancuronium and atracurium caused significant increases in heart rate, while vecuronium induced little change. Systemic vascular resistance decreased significantly from 1515 dyn s cm-5 to 1200 dyn s cm-5 following atracurium. Cardiac index was increased transiently in the atracurium group, but a more sustained increase was observed following pancuronium. Nine patients in the atracurium group showed skin flushing and one developed skin weals.

Dose-response studies with pancuronium, vecuronium and their combination.

Pancuronium, vecuronium and a combination of these were administered in an incremental fashion to study any potentiation of effect with the combination of the two relaxants. The ED95 (dose producing a 95% block) of the combination was 29 micrograms kg-1 for each component in comparison to 57 micrograms kg-1 for vecuronium and 59 micrograms kg-1 for pancuronium. The dose-response curves for the three groups did not differ from each other and no potentiation was demonstrated.