A Trial to Assess the Efficacy and Safety of 400mg/Day Lacosamide in Subjects With Painful Diabetic Neuropathy

The purpose of this trial is to assess whether 400mg/day of lacosamide is effective in reducing pain caused by distal diabetic neuropathy. Two dose-escalation schemes for lacosamide will be used to further determine the efficacy of the "standard" scheme and to evaluate the efficacy and safety of a more rapid titration scheme. Subjects will be randomly assigned to one of three treatment groups. Subjects in two of the groups will receive lacosamide at a dose of 400mg/day, but different dose-escalation schemes will be used to reach this final dose. The third group of subjects will receive a placebo. Subjects will have a 2 in 3 (66 %) chance of getting lacosamide. The maximum lacosamide dose in this trial will be 400mg/day. The maximum treatment duration will be 18 weeks, including a two-week Pre-Treatment Phase and a 12 weeks period on a stable dose of lacosamide or placebo.