BACKGROUND: Rocuronium produce intense discomfort on IV injection in conscious patients. The purpose of this study was to evaluate the incidence and severity of pain associated with IV injection of rocuronium in conscious patients and to determine the efficacy of different doses of IV lidocaine at minimizing injection pain.

METHODS: The author evaluated 120 in-patients undergoing various elective surgeries. Patients were randomized into four groups of 30 patients for this blind, prospective study. After tourniquet application on the forearm, the patients were given saline (3 ml) (Group I, n = 30), lidocaine 20 mg (Group II, n = 30), lidocaine 40 mg (Group III, n = 30), or lidocaine 60 mg (Group IV, n = 30) diluted in a 3 ml solution. The occlusion was released after 20 seconds and rocuronium 0.6 mg/kg was injected over 10 seconds. The patients were observed and asked immediately if they had pain in the arm; responses were assessed. Five mg/kg of thiopental sodium was injected intravenously, 30 seconds after the administration of rocuronium.

RESULTS: The incidence of pain was 86.7% in group I and was significantly lower group II (60.0%), group III (36.3%), and in IV (P <0.05). In addition, patients pretreated with lidocaine were less likely to suffer moderate to severe pain. But, pain incidences and severities were similar in those that received 40 mg or 60 mg of lidocaine.

CONCLUSIONS: Lidocaine was effective at relieving rocuronium-induced and doses of 40 mg and 60 mg of lidocaine were most effective.