Safety and Efficacy of Intravenous Lidocaine for Pain Management in the Emergency Department: A Systematic Review

Study objective We evaluate the safety and efficacy of intravenous lidocaine in adult patients with acute and chronic pain who are undergoing pain management in the emergency department (ED). Methods We searched Ovid CENTRAL, Ovid EMBASE, and Ovid MEDLINE databases for randomized controlled trials and observational studies from inception to January 2017. Efficacy outcomes included reduction in pain scores from baseline to postintervention and need for rescue analgesia. Safety outcomes included incidence of serious (eg, cardiac arrest) and nonserious (eg, dizziness) adverse events. We used the Cochrane Collaboration tool and a modified Newcastle-Ottawa Scale to evaluate the risk of bias across studies. The Grading of Recommendations Assessment, Development and Evaluation approach was used to evaluate the confidence in the evidence available. Results From a total of 1,947 titles screened, 61 articles were selected for full-text review. Eight studies met the inclusion criteria and underwent qualitative analysis, including 536 patients. The significant clinical heterogeneity and low quality of studies precluded a meta-analysis. Among the 6 randomized controlled trials included, intravenous lidocaine had efficacy equivalent to that of active controls in 2 studies, and was better than active controls in 2 other studies. In particular, intravenous lidocaine had pain score reduction comparable to or higher than that of intravenous morphine for pain associated with renal colic and critical limb ischemia. Lidocaine did not appear to be effective for migraine headache in 2 studies. There were 20 adverse events reported by 6 studies among 225 patients who received intravenous lidocaine in the ED, 19 nonserious and 1 serious (rate 8.9%, 95% confidence interval 5.5% to 13.4% for any adverse event; and 0.4%, 95% confidence interval 0% to 2.5% for serious adverse events). The confidence in the evidence available for the outcomes evaluated was deemed to be very low because of methodological limitations, including risk of bias, inconsistency, and imprecision. Conclusion There is limited current evidence to define the role of intravenous lidocaine as an analgesic for patients with acute renal colic and critical limb ischemia pain in the ED. Its efficacy for other indications has not been adequately tested. The safety of lidocaine for ED pain management has not been adequately examined.