Priming with Atracurium Efficiently Suppresses Etomidate-induced Myoclonus

Introduction: Etomidate is a hypnotic drug widely used as an intravenous anesthetic induction agent. The incidence of etomidate-induced myoclonus has been reported as much as 50-80% after induction making it an undesirable drug for induction.

Objective: Our aim is to use a priming dose of atracurium to suppress etomidate-induced myoclonus during induction of anesthesia.

Methods: In a double-blinded clinical trial 80 patients were randomly given either atracurium (20% of ED95 × kg) or saline as a priming agent. Then, induction of anesthesia was performed using 0.4 mg/kg etomidate. Age, weight, body mass index, bispectral index (BIS) monitor, and duration and grade of myoclonus were recorded.

Results: The demographic characteristics, age, body mass index, BIS score, and weight were not significantly different between the atracurium (ATRA) priming group and control groups. The binomial regression model showed that BMI was an independent predictor variable for myoclonus (OR: 2.1, CI 95%: 1.7-7.5, p = 0.032). In this model, adjusted odds ratios (OR) of myoclonus (multivariate logistic regression analysis) in the control group was 6.6 (95% CI: 1.5-9.7, p = 0.013).

Conclusion: Low-dose atracurium priming could effectively suppress etomidate-induced myoclonus.