ABSTRACT
BACKGROUND: Succinylcholine is metabolized by plasma cholinesterase (PChE). When it was pretreated by small doses of nondepolarizing muscle relaxants in order to minimize the side effects, there are evidences to be associated with alteration in the duration of action. This study is investigated whether the responses would be related to the enzymatic activities. METHODS: In 21 adult patients, ASA class I or II, PChE levels were measured by the modified Garry method after induction of anesthesia (control value) and at 3, 10, 20 and 30 min following administration of pancuronium 0.1 mg/kg, vecuronium 0.1 mg/kg and atracurium 0.5 mg/kg. Data were expressed as mean (SEM). RESULTS: The levels of PChE were significantly lower (p<0.05) than the control values at 3, 10, 20 and 30 min after given pancuronium as 4764 (270), 4777 (261), 4796 (306) and 4740 (332) IU/L respectively and after given vecuronium as 5004 (341), 5051 (329), 4969 (340) and 4960 (340) IU/L respectively whereas enzyme levels after given atracurium were not significant differences to compare the control values as 5153 (336), 5136 (320) 5124 (312) and 5151 (275) respectively. CONCLUSIONS: The results of present study show that both pancuronium and vecuronium may possibly inhibit PChE activity but this was not affected by atracurium.