Rocuronium is a non depolarizing muscle relaxant of rapid onset and of intermediate action duration. It is particularly suitable for short operation and rapid control airway. But, intravenous rocuronium cause pain and a withdrawal movement. The purpose of this study was to evaluate the effect of intravenous lidocaine on pain and withdrawal movement in patients receiving rocuronium.

The study was approved by our institutional review board, and informed consent was obtained from all patients. One hundred and twenty patients, ASA physical status 1-2 undergoing general anesthesia for elective surgery were randomly enrolled. Allergy history to trial drug, chronic pain, pregnancy, patient on analgesics, difficult vein access and deeply sedated patients were excluded. Patients were not premedicated, and had a 20-18 G intravenous catheter inserted into a hand dorsum before operation. On arrival in the operation room, routine non-invasive monitors were placed and the free flow of intravenous fluid without edema, redness or hardness was confirmed. A subparalyzing dose of rocuronium 0.06 mg/kg (RS group) or vecuronium 0.01 mg/kg (VS group) was administered after 2 ml of 0.9% NaCl in one group, and a subparalyzing dose of rocuronium 0.06 mg/kg (RL group) or vecuronium 0.01 mg/kg (VL group) was administered after 2 ml of 2% lidocaine injection in a second group. All patients then received 5 mg/kg of 2.5% thiopental sodium and 0.6 mg/kg rocuronium (RS and RL group) or 0.1 mg/kg of vecuronium (VS and VL group). Muscle relaxant-induced pain and withdrawal movements were assessed using 4-grade scales (0-3). Vein redness was measured just after administration and vein hardness five minutes after intubation using 4-grade scales (0-3).

Incidence of pain (8.2 times) and withdrawal movement (6.2 times) was more frequent in the rocuronium group than in the vecuronium group (P< 0.01). Lidocaine pretreatment decreased the incidence of pain significantly (5.7 times, P < 0.01).

Rocuronium causes more pain and withdrawal movements than vecuronium. Lidocaine pretreatment significantly reduced the incidence and severity of pain, and withdrawal movements in both groups.