CISATRACURIUM BESILATE - A REVIEW OF ITS PHARMACOLOGY AND CLINICAL POTENTIAL IN ANESTHETIC PRACTICE

Cisatracurium besilate (besylate) is a nondepolarising neuromuscular b locking agent with an intermediate duration of action. It is the R-cis ,R'-cis isomer of atracurium besilate and is approximately 3-fold more potent than the mixture of isomers that constitute the parent drug. T he ED95 for cisatracurium besilate (dose required to produce 95% suppr ession of twitch response to nerve stimulation) in adults is 0.05 mg/k g during N2O/O-2 opioid anaesthesia. As for atracurium besilate, the p rimary route of elimination of cisatracurium besilate is by spontaneou s degradation. Cisatracurium besilate is not associated with dose-rela ted histamine release (at bolus doses of less than or equal to 8 x ED9 5) and, consistent with this, has demonstrated cardiovascular stabilit y in both healthy patients (less than or equal to 8 x ED95) and those with coronary artery disease (less than or equal to 6 x ED95). In clin ical trials, cisatracurium besilate has been used successfully to faci litate intubation (at 2 to 4 x ED95) and as a muscle relaxant during s urgery and in intensive care. Compared with vecuronium, cisatracurium besilate was associated with a significantly faster recovery after con tinuous infusion in patients in intensive care. Relative to atracurium besilate, cisatracurium besilate has a lower propensity to cause hist amine release, is more potent but has a slightly longer onset time at equipotent doses. It also offers a more predictable recovery profile t han vecuronium after prolonged use in patients in intensive care. Thus , comparative data provide some indication of the potential of cisatra curium besilate as an intermediate-duration neuromuscular blocking age nt but further comparisons with other like agents are required to defi ne precisely its relative merits.