Timing and side effects of flumazenil for dental outpatients receiving intravenous sedation with midazolam.

We studied the timing and side effects of flumazenil treatment for 10 healthy volunteers and 46 dental outpatients who received intravenous sedation with midazolam. For the volunteers, vital signs were monitored before and after intravenous injection of midazolam and flumazenil. In addition, grip strength, signs and symptoms, and performance on the Romberg's test and addition tests were evaluated 30 min and 60 min after midazolam injection as well as after flumazenil injection. There were no significant changes in vital signs before, immediately after, or 50 min after injection of flumazenil, the latter time corresponding to the half-life of the drug. Thus, awakening from sedation was associated with no effects on the cardiovascular or respiratory systems. Distinct effects of flumazenil were demonstrated by the Romberg's test and the assessment of sedation status. Flumazenil had no effect on the outcome of the addition test. For the outpatients, sedation status and signs and symptoms were studied in patients undergoing procedures lasting 30 min or less (group S) and those undergoing procedures lasting 31 to 60 min (group L). Three patients in group S and one in group L had signs and symptoms of resedation. After treatment with flumazenil, abnormalities such as excitability and nausea were reported by only two patients in group L. One patient in group S had drowsiness that did not resolve after injection of flumazenil and continued until the following day. Our results indicate that flumazenil should be given at least 60 min after intravenous sedation with midazolam in dental outpatients. Moreover, caution should be exercised with regard to the potential side effects of flumazenil.