Cisatracurium besilate. A review of its pharmacology and clinical potential in anaesthetic practice.

Cisatracurium besilate (besylate) is a nondepolarising neuromuscular blocking 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. The ED95 for cisatracurium besilate (dose required to produce 95% suppression of twitch response to nerve stimulation) in adults is 0.05 mg/kg during N2O/O2 opioid anaesthesia. As for atracurium besilate, the primary route of elimination of cisatracurium besilate is by spontaneous degradation. Cisatracurium besilate is not associated with dose-related histamine release (at bolus doses of < or = 8 x ED95) and, consistent with this, has demonstrated cardiovascular stability in both healthy patients (< or = 8 x ED95) and those with coronary artery disease (< or = 6 x ED95). In clinical trials, cisatracurium besilate has been used successfully to facilitate intubation (at 2 to 4 x ED95) and as a muscle relaxant during surgery and in intensive care. Compared with vecuronium, cisatracurium besilate was associated with a significantly faster recovery after continuous infusion in patients in intensive care. Relative to atracurium besilate, cisatracurium besilate has a lower propensity to cause histamine release is more potent but has a slightly longer onset time at equipotent doses. It also offers a more predictable recovery profile than vecuronium after prolonged use in patients in intensive care. Thus, comparative data provide some indication of the potential of cisatracurium besilate as an intermediate-duration neuromuscular blocking agent but further comparisons with other like agents are required to define precisely its relative merits.