Abstract
Light surgical anaesthesia lasting 12-15 min was produced by metomidate at 50 mg/kg and by etomidate at 30 mg/kg after intraperitoneal injection. Full surgical anaesthesia lasting about 160 min was achieved after subcutaneous injection of a metomidate-fentanyl mixture (60 mg/kg:0·06 mg/kg) and this proved superior to etomidate-fentanyl given subcutaneously or intraperitoneally. It was concluded that metomidate-fentanyl is superior to pentobarbitone and tribromoethanol as an injectable anaesthetic for mice.