Comparative assessment of dexmedetomidine and butorphanol for attenuation of etomidate-induced myoclonus: A double-blind, randomised controlled study.

Abstract

Etomidate is a popular induction agent, but its use is associated with myoclonus in 50%-80% of non-premedicated patients. This study aims to compare dexmedetomidine and butorphanol for their relative efficacy in preventing etomidate-induced myoclonus. This randomised study was conducted after obtaining institutional ethical committee clearance and written informed consent from sixty American Society of Anesthesiologists (ASA) I or II consenting patients between 18 and 60 years of age of either sex who had been scheduled for elective surgeries under general anaesthesia. Patients were randomly allocated to dexmedetomidine 0.5 μg/kg (Group D) or butorphanol 0.015 mg/kg (Group B). Both the drugs were given as an infusion over a period of 10 min before induction of anaesthesia. The primary outcome was the incidence of myoclonic movements after etomidate, and the secondary outcomes were the severity of myoclonus, changes in the haemodynamic parameters and incidence of airway complications. Normally distributed variables were compared using Student's t-test, and non-normally distributed variables were compared using Mann-Whitney U test. Qualitative data were analysed using Chi-square/Fisher's exact test. A P-value <0.05 was considered significant. The incidence of etomidate-induced myoclonus was significantly higher in group B compared to group D (P = 0.035). The median (interquartile range [IQR]) of myoclonus grade in patients of group D was 0.00 (0.00-3.00), and group B was 2.50 (0.00-3.00) (P = 0.035). Haemodynamics and airway-related complications were comparable between the groups. Dexmedetomidine was more effective than butorphanol in preventing etomidate-induced myoclonus.