Background: Considering the dramatic increasing rate of diabetes and consequently its related complications, most importantly diabetic peripheral neuropathy (DPN), challenges regarding proper treatment of DPN and its effect on the quality-of-life and care of diabetic patients, the aim of this current study is to evaluate the effect of intradermal botulinum toxin type A (BTX-A) injections on pain symptoms of patients with diabetic neuropathic pain.
Materials and methods: In this randomized double-blind placebo-controlled clinical trial study, diabetic patients aged <70 years with neuropathic pain in both feet were enrolled. Diabetic neuropathy (DN) in selected patients was diagnosed using DN4 questionnaire and nerve conduction velocity examinations. They randomized in two intervention (BTX-A injection/100 unit, N = 20) and placebo groups (normal saline injection, N = 20). The outcome of injection on diabetic neuropathic pain was assessed using neuropathy pain scale (NPS) and visual analog scale (VAS) score and compared in two studied groups.
Results: There was no significant difference in DN4, NPS and VAS scales of studied population after intervention in the placebo group. Intradermal injection of BTX-A reduced NPS scores for all items except cold sensation (P = 0.05). It reduced DN4 scores for electric shocks, burning, pins and needles and brushing (P < 0.05). According to VAS scale 30% and 0% of patients in intervention and placebo groups have no pain after intervention (P = 0.01).
Conclusion: Intradermal injection of BTX-A is a well-tolerated agent that has a significant effect on DPN pain.
Keywords: Botulinum toxin type A; diabetic peripheral neuropathy; pain.