Comparison of Premedication with Low-Dose Midazolam Versus Etomidate for Reduction of Etomidate-Induced Myoclonus During General Anesthesia for Electroconvulsive Therapy: A Randomized Clinical Trial

BACKGROUND: A variety of anesthetics including methohexital, thiopental sodium, propofol, ketamine, and etomidate are used for electroconvulsive therapy (ECT), each accompanied by adverse effects that can cause unpleasant experiences for patients. Etomidate-induced myoclonus is among the adverse effects. We attempted to assess the effect of premedication with low-dose midazolam compared to etomidate on the reduction of this complication. OBJECTIVES: This study was designed to compare the effectiveness of low-dose etomidate and low- dose midazolam to suppress etomidate-induced myoclonus in ECT. METHODS: This randomized double-blinded clinical trial was conducted on 132 patients who were candidates for ECT. They were divided into three groups of 44 patients to receive 0.015 mg/kg midazolam, 0.03 mg/kg etomidate, or placebo. Independent t-test and chi-square test were used for comparison of variables. RESULTS: The frequency of myoclonic movements during anesthesia was different between the three groups (P value < 0.001). Myoclonic movements were significantly lower in the midazolam group than in the placebo (P value < 0.001) and etomidate (P value = 0.002) groups. In addition, the intensity of myoclonic movements was significantly higher in the midazolam group than in the placebo and etomidate groups (P value < 0.001). CONCLUSIONS: Low-dose midazolam (0.015 mg/kg) before anesthesia induction with etomidate was accompanied with significantly lower incidence and intensity of myoclonus than low-dose etomidate (0.03 mg/kg).