Evaluation of sodium valproate low dose efficacy in radicular pain management and it's relation with pharmacokinetics parameters

Background: Radiculopathy due to lumbar or cervical disc disease is the most common chronic neuropathic pain in adults. The aim of present study was evaluation of low dose of sodium valproate on radicular pain and determining VPA pharmacokinetics. Materials and Methods: In this double blind randomized placebo control clinical study, 80 patients with established lumbar or cervical radicular pain, have been randomly allocated into two study groups: 40 have received sodium valproate 200 mg/day and Celecoxib 100 mg/day and acetaminophen 500 mg PRN as rescue medication, and second group has received placebo, Celecoxib and acetaminophen. Quantitative assessment of pain was done by visual analogue scale (VAS) prior to perform the intervention and after ten days (treatment duration). Blood sample has been taken for determining mean through concentration after five half-lifes. Evaluation of plasma concentration of VPA and that of efficacy on pain score relationship by comparing VAS before and after the therapy was done. Results: Group A and B have demonstrated significant alleviation in mean VAS score; -21.97 +/- 25.41, -14.39 +/- 23.03 respectively (P < 0.001). The mean plasma concentration of VPA in group A was: 26.9 +/- 13.5 mg/L. Moreover, no significant correlation was seen between pain score with age, gender, and weight (p > 0.05). Conclusion: Low dose of sodium valproate especially together with NSAIDs demonstrated good efficacy in lumbar and cervical radicular pain management.