Midazolam for patients undergoing upper gastrointestinal endoscopy: A prospective, single-blind and randomized study to determine the appropriate amount and time of initiation of endoscopy

Background and Aims: Midazolam is currently the most used sedative agent in endoscopy. The present study was designed to examine the appropriate dose of midazolam, time of initiation of endoscopy after midazolam infusion, and to prove the necessity of flumazenil as an antidote. Methods: One hundred and eighty patients undergoing diagnostic gastroscopy were assigned three different amounts of intravenous midazolam in prospective, single-blinded and randomized setting as follows: (i) group I 0.03 mg/kg midazolam; (ii) group II 0.06 mg/kg midazolam; and (iii) group III 0.09 mg/kg midazolam. Endoscopy was initiated 30, 60 and 90 s after infusion of midazolam within each group. After endoscopy, patients were divided into two groups, one receiving flumazenil and one placebo in a double-blind fashion. The ease of the procedure, the conscious sedative state, the paradoxical response, the level of satisfaction and anterograde amnesia were assessed using a 100 mm visual analog scale. Results: The endoscopist's assessments were not changed by the different doses of midazolam; however, significant differences were observed in the paradoxical responses (P < 0.05). The level of satisfaction with endoscopy was notably different between group I and the other two groups (P < 0.05). Amnesia was boosted according with increasing doses of midazolam (P < 0.05). The time until discharge after endoscopy was significantly different between group III and the other two groups (P < 0.05) and the discharge time was reduced in the flumazenil subgroup compared with the placebo subgroup in group III (P < 0.05). Group II (0.06 mg/kg) reported good levels of satisfaction, fewer paradoxical responses and short discharge time without any side-effects. Comparing the time of initiation of endoscopy (at 30, 60 and 90 s after midazolam) in each group, there were no significant differences in the level of satisfaction, conscious sedative state and amnesia. Conclusions: Midazolam should be administered at a dose of 0.06 mg/kg and the endoscopy should be initiated 30 s after midazolam injection for appropriate effects without any side-effects. Flumazenil is not necessary, except in the case of the use of a high dose (above 0.09 mg/kg) of midazolam.