INTRODUCTIONCisatracurium besilate is a cis-cis isomer (51W89:1R-cis 1'R-cis atracurium), one of the 10 stereoisomers of atracurium that constitutes 15% of the atracurium mixture, an intermediate duration non-depolarising neuromuscular blocking drug. It is about three to four times more potent than atracurium and devoid of cardiovascular side effects in doses of upto 8 times of ED95. The ED95 of cisatracurium is 0.05mg/kg.
1-5The rate limiting step in the degradation of cisatracurium is Hoffmann degradation.(organ independent elimination) to form laudanosine and monoquaternary alcohol. 77% of drug is cleared via Hoffmann degradation which is a ph and temperature dependent process, rest 23% of drug get cleared through organ dependent means, and renal elimination accounts for 16% of this. Hydrolysis by non-specific esterases is not an important pathway for cisatracurium degradation. It is not associated with histamine release in humans. Although the liver and kidneys play only a small role in the excretion of cisatracurium besilate, urinary and hepatic elimination pathways are important for the metabolites of laudanosine.
5-8The total body clearance (CL), steady-state Vd and elimination half-life of cisatracurium besilate in patients with normal organ function are approximately 0.27 to 0.34 L/h/kg (4.7 ml/min/kg), 0.11 to 0.16 L/kg and 22 to 35 minutes, respectively. The volume of distribution (Vd) ABSTRACT Background: Cisatracurium is one of the cis-cis isomer of atracurium (51W89:1R-cis 1'R-cis atracurium) an intermediate duration non-depolarising neuromuscular blocking drug and is devoid of histamine release. However, 2× ED95 dose of cisatracurium does not provide satisfactory intubating condition. The recommended intubating dose of cisatracurium is 3 ×ED95. The objective of this study was to evaluate and compare duration of action, hemodynamic effects and any adverse effects for different doses of cisatracurium. Methods: After Institutional Ethical Committee approval and informed patient consent, 80 patients of ASA I and II in the age group of 20-60 years were selected and included in the study. Patients were divided in two groups of 40 each, group A received intravenously 3×ED95 (0.15 mg/kg) loading dose of cisatracurium and group B received intravenously 4×ED95 (0.2 mg/kg) loading dose of cisatracurium. Results: After induction, MAP and HR shows decrease in both groups but neither statistically nor clinically significant. Better hemodynamic stability and longer duration of action was found in group B compared to group A. No adverse effects noted in both groups. Conclusions: 4×ED95 dose of cisatracurium provides longer duration of action and more stable hemodynamic status than 3×ED95. No associated signs of histamine release were detected clinically.