Efficacy and safety evaluation of pregabalin treatment over 52 weeks in patients with diabetic neuropathic pain extended after a double‐blind placebo‐controlled trial

Aims/Introduction: Diabetic peripheral neuropathy (DPN) is often associated with pain, and thus a new treatment option is anticipated. We recently showed the efficacy of pregabalin in a randomized, double‐blind, placebo‐controlled, 14‐week trial in Japanese patients with painful DPN. In the present study, we evaluated the long‐term efficacy and safety of pregabalin for the relief of painful DPN. Materials and Methods: A total of 123 patients were enrolled in a 52‐week open‐label study, from among those who participated in the preceding double‐blind trial. The subjects received pregabalin 150–600 mg/day. Pain intensity was measured using the short‐form McGill pain questionnaire (SF‐MPQ: total score, visual analog scale and present pain intensity). Results: The efficacy parameter SF‐MPQ showed a decrease over the treatment period. The changes in visual analog scale and present pain intensity at the final evaluation were −25.4 mm and −0.7, respectively, suggesting an analgesic effect of pregabalin. Commonly reported adverse events were somnolence, weight gain, dizziness and peripheral edema, but most of them were mild to moderate in intensity. No new concerns about safety as a result of long‐term administration of pregabalin were identified. Conclusions: The findings from this trial suggest that long‐term treatment with pregabalin is beneficial for pain relief in patients with DPN. This trial was registered with ClinicalTrials.gov (no. NCT00553280). (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00122.x, 2011)