Nalbuphine pretreatment for prevention of etomidate induced myoclonus: A prospective, randomized and double-blind study

Background and Aims: Etomidate induced myoclonus (EM) is a common and hazardous sequel. Premedication with a number of opioids has been shown to effectively attenuate EM. However, there is no reported literature evaluating the effect of nalbuphine pretreatment on EM. The present study was designed to evaluate the efficacy of 0.2 mg/kg nalbuphine intravenous (IV) pretreatment for prevention of EM. Material and Methods: This prospective randomized double-blind and placebo controlled study was conducted in a medical college associated tertiary hospital. One hundred patients undergoing elective surgeries under general anesthesia were randomly allocated to one of two groups to receive: 10 ml of normal saline (Group I) or 0.2 mg/kg nalbuphine in 10 ml of normal saline (Group II) 150 s before injection etomidate 0.3 mg/kg administered IV over 20 s. The patients were assessed for the presence and severity of etomidate induced vascular pain (EP) and EM while injecting etomidate and for the next 2 min, respectively. The patients were monitored for sedation, nausea/vomiting, headache, dizziness, and respiratory depression for 24 h postoperatively. Student's t-test, Chi-square test, or Fisher exact test were used wherever appropriate and P < 0.05 was considered statistically significant. Results and Conclusion: Both the groups were comparable with respect to demographic characteristics. Nalbuphine pretreatment significantly reduced the incidence (20% vs. 72%; respiratory rate = 0.294, 95% confidence interval: 0.160-0.496, P < 0.01) and severity of EM without any significant increase in the incidence of adverse effects. Nalbuphine 0.2 mg/kg IV pretreatment significantly reduces the incidence and severity of EM with side-effect profile comparable to saline placebo.