New neuromuscular blocking drugs.

The new nondepolarizing neuromuscular blocking drugs have specific advantages over succinylcholine. Rocuronium has an onset of action that is almost as rapid as that of succinylcholine and may be useful in patients with residual gastric contents. This drug may replace vecuronium, since the two agents are otherwise similar. The onset of action of mivacurium is similar to that of atracurium, but recovery from the blockade is more rapid (if the plasma cholinesterase level is normal), making mivacurium useful for short procedures. Although pipecuronium and doxacurium have minimal effects on the cardiovascular system, their long and variable onset and duration of action limit their usefulness. The need for either drug is questionable. There is still a need, however, for a nondepolarizing drug that has an onset of action as rapid as that of succinylcholine but a duration of action similar to that of mivacurium, with no adverse cardiovascular effects and clearance from the body that is independent of organ function.