A Water‐soluble Benzodiazepine, RO 21–3981, for Induction of Anesthesia

Diazepam, a benzodiazepine, is widely used to produce basal narcosis prior to anesthesia because of its effectiveness and lack of cardiorespiratory side effects. The venous irritation or occasional phlebitis related to its insolubility in water is a distinct drawback.1–3 Dilution of diazepam and prior administration of a local anesthetic have been used to decrease the pain on injection.4 These maneuvers, however, do not prevent phlebitis in the veins of animals.4 A new water-soluble benzodiazepine, RO 21–3981 (8-chloro-6(2-fluorophenyl)-l -methyl-4H-imidazo-[l,5-a][l,4]benzodiazepine maleate), has been shown in animal studies to have central nervous system depressant properties similar to those of diazepam but with approximately twice the potency.§ Based upon unpublished studies,§ 0.15 mg/kg is the suggested induction close of RO 21–3981. We compared RO 21–3981, diazepam, and thiopental as agents for the intravenous induction of general inhalational anesthesia and evaluated the differences in induction times, cardiorespiratory changes, venous irritation, retrograde or antegrade amnesia, and patient acceptability.