Reversal of central benzodiazepine effects by intravenous flumazenil after conscious sedation with midazolam and opioids: a multicenter clinical study. The Flumazenil in Intravenous Conscious Sedation with Midazolam Multicenter Study Group II.

The efficacy and safety of flumazenil in antagonizing the central effects of the benzodiazepine midazolam was demonstrated in patients in whom conscious sedation was induced with midazolam plus an opioid (fentanyl, meperidine, or morphine). In a double-blind, multicenter study, 240 patients were administered flumazenil postoperatively at an average intravenous dose of 0.7 mg (7 ml) and 114 patients were administered an average dose of 9 ml placebo. Complete reversal of sedation was observed in 80% of flumazenil-treated patients and 30% of placebo-treated patients 5 minutes posttreatment. In 87% of patients who responded to flumazenil, the level of alertness was maintained throughout the 180-minute observation period. Midazolam-impaired psychomotor performance returned to normal 5 minutes posttreatment in 80% of the flumazenil-treated patients and 28% of the placebo-treated patients. Flumazenil was less effective in reversing midazolam-induced amnesia, with only 70% of flumazenil-treated patients (and 15% of placebo-treated patients) able to recall the picture shown them at the 5-minute assessment, and fewer patients able to recall pictures shown at later times. Flumazenil was well tolerated, although adverse effects were reported slightly more often than in the placebo group. The most frequent adverse events in both groups were dizziness and nausea. Vital signs were not affected.