IRCT2017012932277N1 IRCT 2017-07-19 The vice chancellor for research affairs of Shahid Beheshti University of Medical Sciences Identification of the probable mechanisms of Duloxetine and Pregabalin involving in treatment of neuropathic pain of type 2 diabetic patients The comparison of duloxetine and pregabalin effects on plasma concentration of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) in type 2 diabetic patients and the role of these mediators in neuropathic pain 2017-08-01 anticipated 60 Complete https://irct.ir/trial/25182 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment. N/A Condition 1: Non-insulin-dependent diabetes mellitus. Condition 2: Pain due to diabetic polyneuropathy. Condition 3: Autonomic neuropathy. Intervention 1: Duloxetine group: Duloxetine 30 and 60 mg capsules, formulated by Sobhan pharmaceutical factory, Duloxetine 30 mg capsules will be prescribed once daily at first week, afterward, Duloxetine 60 mg capsules will be prescribed once daily for seven more weeks and before these eight weeks Duloxetine 30 mg placebo capsules (manufactured by Sobhan pharmaceutical factory) will be prescribed once daily for ten days. Intervention 2: Pregabalin group: Pregabalin 75 and 150 mg capsules, formulated by Sobhan pharmaceutical factory, Pregabalin 75 mg capsules will be prescribed twice daily at first week, afterward, Pregabalin 150 mg capsules will be prescribed twice daily for seven more weeks and before these eight weeks Pregabalin 75 mg placebo capsules (manufactured by Sobhan pharmaceutical factory) will be prescribed twice daily for ten days.