Pharmacological and clinical comparative study between atracurium and cisatracurium

Cistracurium besylate is an intermediate acting bis-benzylisoquinolinium neuromuscular blocking drug that is one of the steroisomers of atracurium. Phamacological and clinical studies were carried out in present work to assess some properties of cisatracurium in comparison with atracurium. The pharmacological part of this work included experiments on intact anaesthetized cats [to assess the effect on heart rate and blood pressure, and on isolated tissues to find out the effects of histamine. The clinical part of the study was carried out in 100 ASA I, II of adult patients and categorized into 5 groups, 20 patients in each group. Group I received 0.5 mg/kg atracurium, groups II, III, IV and V received cisatracurium in a doses of 0.1, 0.15, 0.2 and 0.4 mg/kg respectively. The groups has been assessed for intubation conditions, and haemodynamic stability by measuring [H.R.] and arterial [B.P.]. Plasma histamine levels were measured by Elysa technique. Experimental study showed that cisatracurium had no effect on blood pressure or heart rate of anaesthetized cat even in doses up to 4 mg/kg. In comparison, atracurium showed cardiovascular stability within therapeutic doses, but with the dose of 4 mg/kg severe hypotension was produced. Also, cisatracurium showed no effect on the isolated ileum of guinea pig and did not increase the contractile effect of histamine on the isolated guinea pig ileum. On the other hand, atracurium increased the effect of histamine on the ileum. The present clinical study showed that there was excellent to good intubation conditions after 2 minutes in 90% of patients who received 0.5 mg/kg atracurium versus 70% of patients who received the equipotent dose of cisatracurium 0.1 mg/kg. Increasing the dose of cisatracurium to 0.15 mg/kg produces excellent to good intubation conditions in 90% of patients after 2 minutes which increases to 98% of patients with increasing the dose of cisatracurium [0.2 mg/kg and 0.4 mg/kg]. There was no clinical evidence of histamine release in the groups receiving cisatracurium compared to 3 out of 20 patients who had cutaneous flushing following the administration of atracurium. The study showed significant increase in plasma histamine concentrations in atracurium group in comparison to cisatracurium group. Analysis of data obtained from the phamracological and clinical studies in this work demonstrated that cisatracurium provides excellent to good intubating conditions with apparent haemodynamic stability and no dose related changes in histamine concentration make cisatracurium a potentially useful muscle relaxant in clinical practice