Anticonvulsants: Efficacy and tolerability of oxcarbazepine in the treatment of neuropathic pain

Abstract

The objective of this trial was to evaluate the safety, tolerability, and efficacy of oxcarbazepine in the treatment of painful neuropathies. This was an open-label, nine-week trial, consisting of a one-week prospective Screening Phase followed by an eight-week Treatment Phase. Treatment with oxcarbazepine was initiated at 150 mg/day and the daily dose was increased on a 2-3 days basis to tolerability over four weeks, up to 1200 mg/day. This was followed by a four-week fixed-dose Maintenance Phase during which patients were maintained on oxcarbazepine. The primary efficacy variable was the change in the weekly pain rating scale assessed on the VAS of the short-form McGill Pain Questionnaire (SF-MPQ) between the Screening Phase and the Treatment Phase. In addition, the short-form 36 Quality of life (SF-36 QOL) was completed at the baseline visit and at the end of the treatment phase. All analysis were performed on the intent-to-treat population. Twenty patients were enrolled in the trial. The mean daily oxcarbazepine dose during the Maintenance Phase was 870 mg. The mean VAS score dropped from 69.85 during the Screening Phase to 29.45 at the end of the trial (p <0.0001), for a mean reduction of - 40.40 (42.16 %). Moreover there were significant improvements in the total pain score and present pain intensity scores from the SF-MPQ and SF-36 QOL. Oxcarbazepine was well tolerated with the most common adverse events consisting of dizziness, and gastric symptoms. The results suggest that oxcarbazepine administered as monotherapy is an efficacious and safe option for the symptomatic treatment of pain associated with neuropathies. These results will need to be confirmed in large, double-blind, placebo controlled, randomized clinical trials