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

Pharmacological and clinical comparative study between atracurium and cisatracurium

Cisatracuruim besylate is a new intermediate acting non depolarizing muscle relaxant. It is approximately three time more potent than atracurium as a neuromuscular blocking agent. The experimental study revealed that cisatracuruim produced dose dependent inhibition of muscle response to electrical stimulation of the sciatic nerve of anaesthetized cat, which was more potent than that produced by atracurium. Absence of contracture of frog's rectus abdominus after administration of both drugs indicate that depolarization could not be a mechanism of their paralyzing effect. Cisatracurium showed no effect on the blood pressure or heart rate of anaesthetized cat even in doses up to 4 mg / kg which is higher than the dose needed for neuromuscular blocking effect. In comparison, atracurium showed cardiovascular stability within the theraputic doses and even [6 x ED[95]] but with very high dose sever hypotension was produced both, cisatracurium and atracurium showed no effect on the myocardial contractility of isolated rabbite's heart. The comparative clinical study between atracurium and cisatracurium was done on 40 middle age adult patient ASA I and II undergoing elective surgery the patient classified into 2 groups [20 patient in each] group I received atracurium 0.5 mg / kg and Group II received cisatracurium 0.1 mg / kg. The onset time of cisatracurium was slightly longer than that for equipotent dose of atracurium [3.45 +/- 1.05] min versus [2.45 +/- 1.1] min respectively, the clinical effective duration of action, the recovery index and time of atracurium were similar to those of cisatracurium at equipotent dose. As regard to the cardiovascular system both cisatracurium and atracurium showed no significant changes in mean arterial blood pressure and heart rat at the equipotent dose. Cisatracurium is nondepolarizing muscle relaxant with intermediate duration of action, predictable recovery time and a constant pharmacodynamic profile which devoid of cardiovascular or histamin releasing effect and eliminated by non organ dependent hoffman elimination, so it is suitable drug to be introduced into clinical anaesthesia