Intravenous Lidocaine Compared to Fentanyl in Renal Colic Pain Management; a Randomized Clinical Trial

Introduction: Using alpha blockers such as intravenous (IV) lidocaine has been deemed effective in controlling acute pain. Therefore, the current study was designed with the aim of evaluating the efficiency of IV lidocaine in comparison to IV fentanyl in pain management of patients with renal colic in emergency department (ED). Methods: In this double blind clinical trial, 18-65 year old patients that presented to ED with colicky flank pain and met the inclusion criteria of the study were allocated to either lidocaine or fentanyl group using block randomization and compared regarding pain severity 5, 10, 15, and 30 minutes after drug administration. Results: 90 patients with the mean age of 35.75±8.87 years were divided into 2 groups of 45 (90% male). The 2 groups were not significantly different regarding the studied baseline variables. Pain severity was not significantly different between the 2 groups at various times after injection. Treatment failure rate 15 minutes after injection was 44.4% (20 cases) in IV lidocaine and 17.8% (8 cases) in IV fentanyl group (p = 0.006). These rates were 26.6% (12 patients) versus 22.2% 30 minutes after injection (p = 0.624). Absolute risk increase of treatment failure in case of using lidocaine was 26.7 (95% CI: 8.3-44.9) in the 15th minute and 4.4 (95% CI: 13.3-22.2) 30 minutes after injection. Number needed to harm (NNH) in treatment with lidocaine 15 and 30 minutes after injection were 4 (95% CI: 2.2-12.0) and 23, respectively. Conclusion: Although mean pain severity was not significantly different between IV fentanyl and lidocaine at various times after injection, treatment failure rate was significantly higher in the IV lidocaine group 15 minutes after injection.