Pretreatment with nafamostat mesilate, a kallikrein inhibitor, to decrease withdrawal response associated with rocuronium.

PURPOSE: This randomized, double-blind, placebo-controlled study was conducted to examine the preventive effect of nafamostat mesilate, a kallikrein inhibitor, on the withdrawal response associated with rocuronium injection. METHODS: Ninety American Society of Anesthesiology (ASA) physical status I or II patients, aged 18-65 years, were randomly divided into two groups that received either a 1.5-ml solution containing 1.5 mg nafamostat mesilate diluted in a 5% glucose solution or a 1.5-ml 5% glucose solution. Anesthesia was induced by 5 mg/kg 2.5% thiopental. After confirming loss of consciousness, a tourniquet was applied to the mid forearm and tightened to block venous flow. The test solution was then administered, 1 min after which the tourniquet was removed and 0.6 mg/kg rocuronium was administered. Each patient's response to rocuronium injection was graded on a four-point scale in a double-blind manner. Activated coagulation time and plasma potassium concentration were measured before and 5 and 10 min after nafamostat administration. RESULTS: The incidence of withdrawal response was 68.9% in the control group and 24.4% in the nafamostat group (P < 0.001). The number of patients showing generalized movement (response 4) with the rocuronium injection was significantly lower in nafamostat group [1 (2.2%)] than the control group [15 (33.3%)], P < 0.001. Five and 10 min after nafamostat administration, measured potassium and activated coagulation time were similar to baseline values. CONCLUSION: Pretreatment with 1.5 mg nafamostat mesilate decreased withdrawal response associated with rocuronium injection.

Remifentanil attenuates muscle fasciculations by succinylcholine.

PURPOSE: The present visual and electromyographic study was designed to evaluate muscle fasciculations caused by succinylcholine in adults pretreated with either remifentanil 1.5 microg/kg or saline. MATERIALS AND METHODS: The effect of remifentanil on succinylcholine-induced muscle fasciculations was studied using a double-blind method in 40 adults. After i.v. pretreatment with either remifentanil 1.5 microg/kg (remifentanil group, n = 20) or an equivalent volume of i.v. saline (saline group, n = 20), patients were anaesthetized with a 2.0 mg/kg of i.v. propofol followed by i.v. succinylcholine 1.0 mg/kg. Intensity and duration of muscle fasciculation following i.v. succinylcholine administration were recorded. Electromyography (EMG) was used to quantify the extent of muscle fasciculation following i.v. succinylcholine injection. Myalgia was evaluated 24 hours after induction time. Serum potassium levels were measured five minutes after i.v. succinylcholine administration and creatine kinase (CK) levels 24 hours after induction time. RESULTS: Compared to saline treated controls, remifentanil decreased the intensity of muscle fasciculations caused by i.v. succinylcholine [fasciculation severity scores (grade 0 to 3) were 2/1/12/5 and 3/13/4/0 (patients numbers) in the saline group and the remifentanil group, respectively, p < 0.001]. The mean (SD) maximum amplitude of muscle action potential (MAP) by EMG was smaller in the remifentanil group [283.0 (74.4) microV] than in the saline group [1480.4 (161.3) microV] (p = 0.003). Postoperative serum CK levels were lower in the remifentanil group (p < 0.001). Postoperative myalgia was not different between the two groups. CONCLUSION: Remifentanil 1.5 microg/kg attenuated intensity of muscle fasciculations by succinylcholine.