Inclusion Criteria:  Patients with pain due to bilateral peripheral neuropathy caused by type 2 diabetes mellitus. HbA1c of greater than 7% A total symptoms score (TSS) of 7.5 points, The daily pain must be present for at least 6 months, and the diagnosis will be confirmed by a score of at least 3 on the Michigan Neuropathy Screening Instrument (MNSI). Patients had to have a mean score of ≥4 when assessed for 24-hour average pain severity on the 11-point Likert scale (from the patient diary prior to randomization).  Exclusion Criteria:  Older subjects with high risks of cardiovascular diseases, Pregnant or breastfeeding, Having a prior renal transplant or current renal dialysis, Patients have a diagnosis of major depressive disorder, generalized anxiety disorder, heavy alcohol drinkers, Significant hepatic or renal disease, Patients on antioxidant therapy, or pentoxyphylline within the last month.