ObjectiveTo systematically assess the effectiveness and safety of I.V. infusion of dezocine for prevention of myoclonus caused by etomidate. MethodsDatabases including PubMed, EMbase, The Cochrane Library (Issue 6, 2014), CNKI, WanFang Data and VIP were electronically searched from inception to May 2014 for randomized controlled trials (RCTs) on I.V. infusion of dezocine for prevention of myoclonus caused by etomidate. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies. Then, meta-analysis was performed using RevMan 5.2.3 software. ResultsTen RCTs were included. The results of meta-analysis indicated that, dezocine could reduce the incidence of myoclonus induced by etomidate (RR=0.24，95%CI 0.12 to 0.45, P<0.000 1), and was better than fentanyl (RR=0.30, 95%CI 0.17 to 0.51, P<0.000 1); dezocine could reduce the amount of etomidate (MD=-4.70, 95%CI -6.62 to -2.79, P<0.000 01); compared with fentanyl, dezocine could reduce the incidence of injection pain (OR=0.25, 95%CI 0.10 to 0.62, P=0.003); dezocine did not increase the incidence of respiratory depression (OR=2.61, 95%CI 0.12 to 56.03, P=0.54). ConclusionI.V. infusion of dezocine before etomidate administration could reduce myoclonus incidence caused by etomidate, reduce the amount of etomidate, and is better than fentanyl; which could also reduce the incidence of injection pain, and not increase the incidence of respiratory depression.