Botulinum Toxin Type A for Neuropathic Pain in Patients With Diabetic Peripheral Polyneuropathy

Inclusion Criteria: * • more than twenty years of age * patients should have 4 or more items positive among the 10 items of the DN4 questionnaire. * persistence of neuropathic pain for more than three months or remission and recurrence of neuropathic pain for more than six months * a pain score of 4 or more on the numeric rating scale Exclusion Criteria: * • neuropathic pain caused by confounding factors other than diabetic neuropathic pain * contraindicated for botulinum toxin type A * a change in pain medication one month prior to study enrollment * a condition involving neuromuscular junction (Ex. Eaton Lambert disease, myasthenia gravis) * person who received botulinum toxin type A within three months prior to study enrollment