Objective: This study was designed to evaluate the efficacy and safety of preinjection of dezocine in preventing etomidate-induced myoclonus. 
Methods: PubMed, Embase, The Cochrane Library, and China National Knowledge Infrastructure (CNKI) were searched to collect relevant randomized controlled trials (RCTs) from inception to July 2016 on the preinjection of dezocine in preventing etomidate-induced myoclonus. Two researchers independently screened literature, extracted data, and evaluated bias risks in accordance with inclusion and exclusion criteria, and then used RevMan 5.2 to perform the meta-analysis. 
Results: A total of six RCTs were included in this study. The meta-analysis showed that 1) the preinjection of dezocine can reduce the incidence of etomidate-induced myoclonus (relative risk [RR] =0.25, 95% CI [0.13, 0.50], P <0.0001), which is consistent with the result of subgroup analysis; 2) the preinjection of dezocine can reduce the incidence of mild, moderate, and severe myoclonus; 3) dezocine was not related to an increasing incidence of etomidate-induced dizziness and nausea (RR =2.83, 95% CI [0.66, 12.08], P =0.6); and 4) dezocine did not reduce heart rates after the administration of etomidate (mean difference =1.06, 95% CI [–4.08, 6.19], P =0.69).
Conclusion: The preinjection of dezocine has the effect of both lowering the incidence of etomidate-induced myoclonus and easing the severity of myoclonus, but without increasing dizziness and nausea or affecting the heart rate.
Keywords: dezocine, etomidate, myoclonus, meta-analysis, RCTs