tokens: Flumazenil ( mean dose , 0 . 76 mg ) or placebo ( mean dose , 8 . 9 ml ) was administered intravenously to 130 and 67 patients , respectively , who had been given diazepam in conjunction with an opioid ( fentanyl , meperidine , or morphine ) for the induction and maintenance of intravenous conscious sedation for diagnostic or therapeutic surgical procedures .