Evaluation of efficacy and safety of gabapentin, duloxetine, and pregabalin in patients with painful diabetic peripheral neuropathy

Aim: To compare the efficacy and safety of gabapentin (GBP), duloxetine (DLX), and pregabalin (PGB) in patients with painful diabetic peripheral neuropathy (DPNP). Methods: A prospective, randomized, open label, 12-week study was conducted. A total of 152 patients with history of pain attributed to DPNP with a minimum 40-mm score on visual analogue scale (VAS) were randomized to receive GBP, DLX, or PGB. The primary efficacy measure was pain severity as measured on 11 point VAS. Secondary efficacy measures included sleep interference score, Patient Global Impression of Change (PGIC), and Clinical Global Impression of Change (CGIC). Assessment of safety was done by recording the occurrence of adverse drug reactions. Data was analyzed using descriptive statistics, Chi square test, analysis of variance (ANOVA), and repeated measures ANOVA. Results: Of total 152 patients, 50 patients received GBP, DLX each while 52 received PGB. A significant reduction in pain score (VAS), sleep interference score, PGIC, and CGIC was seen in all the three treatment groups across time (P<0.05) with no statistically significant difference between the groups. There was a significant interaction between the time and treatment groups (P<0.001) for pain score (VAS), sleep interference score, and PGIC. The improvement in pain scores (VAS) and sleep interference score was higher with PGB compared to DLX and GBP. Adverse drug reactions were mild and occurred in 9.2% of all cases. Conclusions: Monotherapy with GBP, DLX, or PGB Produced a clinically and subjectively meaningful pain relief in patients with DPNP with onset of pain relief being faster and superior with PGB.