A Randomised Controlled Trial to Evaluate the Effects of Flumazenil after Midazolam Premedication in Outpatients Undergoing Colonoscopy

Abstract

The degree of sedation and amnesia, subjective assessment of awakening and side effects after intravenous injection of 3-4 mg midazolam and 1 mg flumazenil or placebo were studied directly after colonoscopy, and on the first and the eight day. A total of 91 patients were studied; 45 patients were given flumazenil and 46 patients a placebo. Five minutes after injection of the test drugs all 45 patients given flumazenil but only 38 patients given the placebo were alert (p = 0.006). All three response criteria (for sedation, amnesia and subjective assessment of awakening) were fulfilled by 84.4 % of the patients given flumazenil and 45.7 % of the patients given the placebo (p = 0.0002). Thirty minutes after injection of the test drugs dizziness, nausea, and fatigue were found in 3 patients given flumazenil and in 10 patients given placebo. One day after colonoscopy 9 of 45 patients (20 %) given midazolam and flumazenil complained of fatigue and 9 of 46 patients (19.5 %) given midazolam and placebo. Eight days (± 1 day) later two patients in each group complained of headache, nausea and fatigue. No patient developed phlebitis at the injection site. Flumazenil seems to be a safe and efficient drug for reversing the sedative effect of midazolam, premedication after colonoscopy. However, resedation due to the effects of midazolam may occur. Flumazenil thus permits administration of a higher dose of midazolam without prolongation of the surveillance time. Improved exploitation of time, space and nursing resources is thus possible without jeopardizing patient safety, although caution is necessary since patients may not be fit to resume all normal activities.