Pharmacological and clinical comparative study between atracurium and cisatracurium

ABSTRACT

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