Anticonvulsants: Oxcarbazepine relieves pain and paresthesias in idiopathic painful sensory neuropathy

Abstract

We conducted an open-label pilot study to assess the safety and efficacy of oxcarbazepine on the severity of sensory symptoms in patients with painful sensory neuropathy (PSN). A total of 10 patients (7 female) with idiopathic painful neuropathy of at least 3 months duration enrolled in the study. Data are reported from 9 patients; one withdrew early. The mean age was 61.3 years (range: 47-70). The study consisted of a 2-4 week screening phase, a 4-week titration phase, 12-week maintenance phase, and a 2-week dose-tapering phase. Oxcarbazepine was initiated at 150 mg BID for 1 week, increased to 300 mg BID at week 2, 450 mg BID at week 3, and 600 mg BID at week 4. Dose adjustments were allowed during the 4-week titration phase. The following assessments were performed: VAS, NSC (Neuropathy Symptom and Change), neurologic exam, vital signs, and recording of any adverse events. The mean and median changes in VAS scores were -32 mm and -48 mm, respectively (p < 0.04). The mean change from baseline to last visit in overall severity score for the 9 questions of the sensory component of the NSC was -5.7 points (p=0.02). Significant decreases of at least 1 point were noted in severity of paresthesias (p=0.031), spontaneous sharp pains (p=0.031), and spontaneous burning discomfort (p=0.016). Five patients discontinued before completion due to adverse events. One was considered unrelated to study drug and two improved with dose reduction but chose to withdraw regardless. Oxcarbazepine is effective in reducing neuropathic pain in PSN. The NSC is a useful outcome measure in trials of interventions for neuropathic pain because it allows for semi-quantitative assessment of change among characteristic neuropathic pain symptoms. A double blind study of the effect of oxcarbazepine on positive sensory symptoms in idiopathic PSN is warranted