Management of diabetic neuropathy by sodium valproate and glyceryl trinitrate spray: A prospective double-blind randomized placebo-controlled study

Objectives: Combination of drugs with different mechanisms of action helps in achieving synergistic analgesic effect in neuropathic pain. Keeping this point in view, the effect and safety aspects of sodium valproate and GTN were assessed alone as well as in combination in this study. Design: Prospective double-blind randomized placebo-controlled study. Material and method: Eighty-seven type 2 diabetics with painful neuropathy were enrolled. Four were excluded: three with HbA1c > 11 while one withdrew consent. The remaining 83 were given either sodium valproate and GTN spray (group A) or placebo drug and GTN spray (group B) or sodium valproate and placebo spray (group C) or placebo drug and placebo spray (group D). Quantitative assessment of pain was done by McGill pain questionnaire, visual analogue score (VAS) and present pain intensity (PPI) at the beginning of the study and after 3 months along with motor and sensory nerve conduction velocities measurements. Results: All the three treatment groups experienced significant improvement in pain score in their drug phase of trial (p < 0.001/ < 0.05) along with some of the electrophysiological parameters. The assessment of the magnitude of therapeutic effect of sodium valproate, GTN and their combination gave numbers needed to treat (NNT) of 7, 5 and 4, respectively. Conclusion: Sodium valproate and GTN are well tolerated and provide significant improvement in pain scores as well as in electrophysiological parameters. (C) 2009 Published by Elsevier Ireland Ltd.