Comparative evaluation of the effect of remifentanil and 2 different doses of esmolol on pain during propofol injection

Background: Propofol is associated with pain during injection, which is stressful to patients. The present study was designed to investigate the analgesic effect of pretreatment with remifentanil and esmolol in minimizing propofol injection pain, compared with placebo. Methods: In a randomized, double-blind, prospective trial, 120 patients, scheduled for elective dental surgery under general anesthesia, were randomized to 1 of the 4 treatment arms (n=30 each) receiving normal saline, remifentanil 0.35μg/kg, esmolol 0.5mg/kg, and 1mg/kg before administration of propofol. During injection of 1% propofol 0.5mg/kg, pain was evaluated by a 4-point score (0=none, 1=mild, 2=moderate, 3=severe). Any adverse effects such as hypotension and bradycardia were recorded during the perioperative periods. Results: In all, 120 patients completed this study. There were no significant differences in terms of demographic data. The incidence of pain on injection of propofol was 11 (36.7%) with remifentanil 0.35μg/kg, 12 (40%) with esmolol 0.5mg/kg, and 11 (36.7%) with esmolol 1mg/kg, compared with 25 (83.3%) with normal saline (respectively, P<0.05). There were no significant differences in the incidence of pain between groups with remifentanil 0.35μg/kg, and esmolol 0.5mg/kg and 1mg/kg. There were no emergence reactions such as hypotension and bradycardia in all groups. Conclusions: Pretreatment with esmolol 0.5mg/kg and 1mg/kg and remifentanil 0.35μg/kg equally decreased pain during propofol injection.