The use of fazadinium in children. An electromyographic study.

To evaluate the use fazadinium in children and to compare it with pancuronium, 64 children aged 6 months to 12 yr received fazadinium 0.75, 1.0, 1.25 mg kg-1 and pancuronium 0.1 mg kg-1 in groups of 16. Neuromuscular transmission was evaluated electromyographically using train-of-four stimuli. The times to first effect, maximum effect, first sign of recovery, reversal and full recovery after reversal were recorded and neuromuscular transmission was monitored continuously until complete recovery was obtained. Duration of satisfactory clinical relaxation and neuromuscular transmission when relaxation became inadequate were recorded. The speed, duration and depth of effect, and the duration and degree of neuromuscular blockade increased significantly depending on dose. Fazadinium was found to be a potent drug providing satisfactory relaxation in a dose of 1.0-1.25 mg kg-1 for operations of medium to long duration in children under light halothane anaesthesia. When relaxation became inadequate neuromuscular transmission still showed marked depression. Duration and degree of blockade of fazadinium and pancuronium were not age-dependent. In all groups the neuromuscular blockade was reversed easily. Apart from the speed of onset of action, pancuronium 0.1 mg kg-1 corresponded to a dose of fazadinium between 1.0 and 1.25 mg kg-1. Train-of-four ratio was found to be more sensitive than single twitch as an index of the recovery of transmission during recovery and in the period after operation.