Rapacuronium: first experience in clinical practice.

Rapacuronium is a new non-depolarizing relaxant with a fast onset and rapid recovery. It was approved for the market in the United States in August 1999. The reasons for its acceptance in practice and the niche it fills are the subject of this review. Rapacuronium has been accepted wherever rapid onset and short duration of action are advantageous. It has received the greatest acceptance in brief outpatient procedures that require tracheal intubation. The average time of recovery to a train-of-four ratio of 80% is about 25 min after a usual intubating dose of 1.5 mg kg-1, when block is reversed. Its rapid onset has led some to use it in rapid-sequence induction, but the exact place in this scenario is still being defined. Its spontaneous recovery is rapid enough that many practitioners do not reverse the block if the procedure is long enough. Data suggest that this is reasonable after 60 min and may even be earlier, even 30 min, if verified by monitoring. The main adverse effects of rapacuronium are bronchospasm, hypotension and tachycardia. Of these, only bronchospasm has had significant clinical impact. These effects are dose related and the recommended dose of 1.5 mg kg-1 may keep problems to a minimum. Because rapacuronium is a new drug with unique properties its use gradually increased in its first year. Because of the problems associated with succinylcholine, rapacuronium may have advantages for brief outpatient procedures and in cases where rapid termination of block is desired, provided its adverse effects can be minimized.