Comparative study of rocuronium and vecuronium on the neuromuscular activity in experimental animals

ABSTRACT

Rocuronium is one of the newest non depolarizing neuromuscular blocking drugs. In this study, the effects of rocuronium and vecuronium as neuromuscular blocking agents on isolated rat phrenic nerve diaphragm and intact gastrocnemius sciatic nerve preparation in the cat were compared. The effect of gradually increasing doses of rocuronium [3-48 mu g /ml] and vecuronium [0.58 mu g/ ml] on the amplitude of contraction of isolated muscle in response to indirect electrical stimulation was recorded. Also, the effect of rocuronium [0.06-0.12 mg / Kg] and vecuronium [0.01-0.02 mg / kg] on the electrically induced gastrocnemius sciatic nerve was studied. Both drugs produced significant dose dependent reductions in the amplitude of rat phrenic nerve diaphragmatic contractions, but the effect of vecuronium was more than rocuronium. On cats gastrocnemius sciatic nerve preparations, the pattern of neuromuscular blockade [magnitude on set to maximum blockade and duration of block] of both drugs was also dose dependent. The results of this study demonstrated that rocuronium had significantly shorter time of onset, less potent with shorter duration of motor block than vecuronium