RESUMEN
This study was undertaken to determine the effect of lidocaine pretreatment on reduction of succinylcholine-induced myalgia in patients undergoing general anesthesia for gynecological surgery. One hundred and thirty-five patients were assigned to one of three groups in a prospective, double blind, randomized manner. Group PS, the control group, received normal saline and succinylcholine 1.5 mg x kg(-1); Group LS, lidocaine 1.5 mg x kg(-1) and succinylcholine 1.5 mg x kg(-1); Group PR, normal saline and rocuronium 0.6 mg x kg(-1). Morphine 0.1 mg x kg(-1) iv was given for premedication and all patients were monitored with a noninvasive blood pressure monitor, ECG and pulse oximetry. Anesthesia was induced with 5 mg.kg(-1) thiopental iv. followed by succinylcholine (Group PS, LS) or rocuronium (Group PR) for tracheal intubation. Following administration of these agents, the presence, and degree of fasciculation were assessed visually on a four point scale by one investigator who was blinded to the drug administered. The blood pressure and heart rate of each patient were monitored on nine occasions. Twenty-four hours later, any myalgia experienced was assessed according to a structured questionaire and graded by a four point scale by one investigator blinded to the intraoperative management. The results indicate that muscle fasciculation was not found in Group PR while the patients in Group LS had a lower incidence of muscle fasciculation than those in Group PS (p < 0.001). At 24 h, the incidence of myalgia was higher in Group PS than in Group LS and PR (p < 0.05). A correlation was not found between the incidence of myalgia and the occurrence of muscle fasciculation. The changes in systolic and diastolic blood pressure and heart rate were not significant among the three groups. In conclusion, where succinylcholine is used, lidocaine is proven to be the useful pretreatment agent for the reduction of postoperative myalgia.