title: Systemic administration of local anesthetics to relieve neuropathic pain: a systematic review and meta-analysis.
abstract: We reviewed randomized controlled trials to determine the efficacy and safety of systemically administered local anesthetics compared with placebo or active drugs. Of 41 retrieved studies, 27 trials of diverse quality were included in the systematic review. Ten lidocaine and nine mexiletine trials had data suitable for meta-analysis (n = 706 patients total). Lidocaine (most commonly 5 mg/kg IV over 30-60 min) and mexiletine (median dose, 600 mg daily) were superior to placebo (weighted mean difference on a 0-100 mm pain intensity visual analog scale = -10.60; 95% confidence interval: -14.52 to -6.68; P < 0.00001) and equal to morphine, gabapentin, amitriptyline, and amantadine (weighted mean difference = -0.60; 95% confidence interval: -6.96 to 5.75) for neuropathic pain. The therapeutic benefit was more consistent for peripheral pain (trauma, diabetes) and central pain. The most common adverse effects of lidocaine and mexiletine were drowsiness, fatigue, nausea, and dizziness. The adverse event rate for systemically administered local anesthetics was more than for placebo but equivalent to morphine, amitriptyline, or gabapentin (odds ratio: 1.23; 95% confidence interval: 0.22 to 6.90). Lidocaine and mexiletine produced no major adverse events in controlled clinical trials, were superior to placebo to relieve neuropathic pain, and were as effective as other analgesics used for this condition.
authors.affiliation: *Department of Neurology, Medical University of South Carolina, Charleston, SC; †Department of Anesthesiology and Critical Care, University of Chicago Hospitals, Chicago, IL; ‡Department of Anesthesiology, and §Institute for Clinical Research and Health Policy Studies Tufts-New England Medical Center, Boston, MA.
authors.forename: Ivo W
authors.initials: IW
authors.lastname: Tremont-Lukats
authors.forename: Vidya
authors.initials: V
authors.lastname: Challapalli
authors.forename: Ewan D
authors.initials: ED
authors.lastname: McNicol
authors.forename: Joseph
authors.initials: J
authors.lastname: Lau
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Carr
mesh_terms: D000779:Anesthetics, Local / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D008012:Lidocaine / Q000627:therapeutic use; D008801:Mexiletine / Q000627:therapeutic use; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D010523:Peripheral Nervous System Diseases / Q000150:complications / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D000779:Anesthetics, Local; D008801:Mexiletine; D008012:Lidocaine