Comparison of pretreatment with low-dose midazolam in combination with fentanyl and midazolam alone on the occurrence of etomidate-induced myoclonus—a randomized, double-blind study

Abstract Background Myoclonus is reported to occur in 50–80% of patients receiving etomidate in the absence of pretreatment. The study aimed to evaluate the efficacy of pretreatment with low-dose midazolam and fentanyl, and midazolam alone to reduce the occurrence of etomidate-induced myoclonus. Sixty patients were randomly divided into 2 groups. In group MF, patients received pretreatment with intravenous (IV) midazolam 0.015mg/kg in a volume of 5 ml normal saline, followed by IV fentanyl 1μg/kg in a volume of 5 ml normal saline. In group M, patients received pretreatment with IV midazolam 0.03mg/kg in a volume of 5 ml normal saline, followed by 5ml of IV normal saline. The test drug was injected over 30 s, and after 120 s, IV etomidate 0.3 mg/kg was injected over 30 s. The patients were observed for 120 s for myoclonus and graded as mild, moderate, or severe. Heart rate, blood pressure, and oxygen saturation were recorded immediately after test drug injection and at every minute for 5 min. Results The demographic parameters and hemodynamic parameters were comparable between the two groups. In group M, the incidence of myoclonus was 36.67% (26.67% mild and 10% moderate) whereas, in the group MF, the incidence of myoclonus was 26.67% (3.33% mild, 16.67% moderate, and 6.67% severe). This incidence of myoclonus was significantly lower in group MF (p=0.030). Conclusions The incidence of etomidate-induced myoclonus is significantly lower in patients pretreated with midazolam and fentanyl combination as compared to midazolam alone. Trial registration Clinical Trial Registry Details: CTRI/2019/05/018920