Abstract

In a randomized, double-blind, placebo-controlled study, the efficacy of flumazenil in reversing the psychomotor, sedative, and amnestic effects of midazolam in elderly patients after surgery under regional anesthesia was examined. Thirty ASA I-III patients older than 63 years undergoing regional anesthesia with midazolam sedation were randomly assigned to receive either intravenous flumazenil ( n = 19) or intravenous placebo ( n = 11) after surgery. After assessments of sedation immediately postoperatively, 0.1 mg/ml flumazenil or placebo was given in 2-ml increments twice, a minute apart, and titrated in further 2-ml increments until patients were awake or until 10 ml had been given. Efficacy of reversal was determined using patient and observer assessments of sedation and simple psychomotor tests administered preoperatively and at five, 15, 30, 60, 120, and 180 minutes after test drug administration. Reversal of amnesia was tested by assessing recall of pictures shown at five, 15, 30, and 60 minutes after drug administration. Time profiles of digit substitution test and observer assessment of sedation data were significantly different between the flumazenil and placebo groups. For observer's assessment of sleep, significant differences were noted between flumazenil and placebo groups only at five, 15, and 30 minutes after test drug administration. A significant difference was noted between flumazenil and placebo patients in the ability to recall pictures shown five and 15 minutes after drug administration, but not pictures shown at 30 or 60 minutes. Within-group analysis demonstrated that loss of difference over time between flumazenil and placebo groups was the result of decreasing effect of both flumazenil and midazolam.