Analgesic effect of duloxetine compared to nortryptiline in patients with painful neuropathy: A randomized, double-blind, placebo-controlled trial

BACKGROUND: Diabetic neuropathic pain (DNP) is a common complication of diabetes and has a profound effect on patients’ quality of life. Therefore. The purpose of the present study was to compare the analgesic effects of duloxetine and nortryptiline in the management of patients with diabetic neuropathy. METHODS: This was a randomized, double-blind, parallel-group, placebo-controlled trial in subjects with a proven diagnosis of DM and suffered from neuropathic pain. Patients were recruited in this study from 20 February 2016 (first patient, first visit) to 22 June 2017 (last patient, last visit), including 5 weeks follow-up. A diagnosis of DNP was based on history, clinical examination, Nerve conduction velocity and Diabetic neuropathy symptom score (more than one point). RESULTS: Both drugs reduced pain when compared with placebo. A significant VAS reduction from 6.4 at baseline to 3.75 at endpoint was observed in the duloxetine group. However, there was no significant difference in the efficacy between nortriptyline and duloxetine based on patient's visual analogue scale (VAS) (p>0.05). No clinically significant changes or serious adverse events were found among treatment groups including changes in vital signs, laboratory assessments, physical examination or electrocardiograms. The decrease in the mean pain intensity was significantly greater in the duloxetine and nortriptyline group compared to the placebo group both in the primary analysis and in the by-visit analysis (p<0.003). CONCLUSION: The present study demonstrates the safety and effectiveness of both duloxetine and nortriptyline in the management of DNP.