Intravenous Amide Anesthetics to Treat Pain Associated with Renal Colic in the Emergency Department: a Systematic Review

INTRODUCTION: Renal colic affects 12% of the U.S. population, accounting for nearly 1% of emergency department (ED) visits. Current recommendations advocate narcotic-limiting multimodal analgesia regimens. The objective of this review is to determine if in patients with renal colic (Population), intravenous (IV) amide anesthetics (Intervention) result in better pain control, lower requirements for rescue analgesia, or less adverse medication effects (outcome) compared to placebo, non-steroidal anti-inflammatory drugs (NSAIDs), or opiates (Comparisons). METHODS: Scholarly databases and relevant bibliographies were searched using a pre-designed systematic review protocol and registered with PROSPERO. Inclusion criteria were: (1) randomized clinical trial (RCT), (2) age ≥ 18 years, (3) confirmed or presumed renal colic, (4) amide anesthetic administered IV. Eligible comparison groups included: placebo, conventional therapy, acetaminophen, NSAID, or opiate. The primary outcome was pain intensity at baseline, 30, 60, and 120 minutes. Trial quality was graded, and risk-of-bias was assessed. RESULTS: Of the 3930 identified references, 4 RCTs (479 participants) were included. One trial (n=240) reported improved analgesia with IV lidocaine (Lido(IV)) plus metoclopramide, compared to morphine. All other trials reported unchanged or less analgesia compared to placebo, ketorolac, or fentanyl. Very severe heterogeneity (I(2)= 88%) precluded pooling data. CONCLUSION: Current evidence precludes drawing a firm conclusion on the efficacy or superiority of Lido(IV) over traditional therapies for ED patients with renal colic. Evidence suggests Lido(IV) may be an effective non-opiate analgesic alliterative; however, it’s efficacy may not exceed that of NSAIDs or opiates. Further study is needed to validate the potential improved efficacy of Lido(IV) plus metoclopramide.