Midazolam Pretreatment Reduces Etomidate-induced Myoclonic Movements

During induction of anaesthesia with etomidate, myoclonic muscle movements are frequent. In this study, pretreatment with a small dosage of etomidate or midazolam was compared with placebo for the prevention of myoclonic muscle movements. Sixty patients, premedicated with oral midazolam, were pretreated in a randomized double-blinded fashion with etomidate 0.05 mg/kg IV, midazolam 0.015 mg/kg IV or normal saline IV (placebo) in three groups of 20 patients each. The pretreatment was followed after 90 seconds by etomidate 0.3 mg/kg IV. One minute after onset of hypnosis, induction of anaesthesia was completed with sufentanil and rocuronium. From the time of pretreatment to completion of anaesthesia, patients were observed for myoclonic muscle movements by a single physician, blinded to group allocation. Myoclonic movements were graded on a scale of 0 to 3. The incidence of myoclonic movements was significantly lower in patients pretreated with midazolam (4 of 20) compared with placebo (18/20) (P<0.01). Midazolam 0.015 mg/kg IV, administered 90 seconds before induction of anaesthesia with etomidate, is effective in reducing etomidate-induced myoclonic muscle movements.