Lacosamide in painful diabetic peripheral neuropathy - A phase 2 double-blind placebo-controlled study

Background: Peripheral diabetic neuropathy affects between 20% and 45% of patients with diabetes. Objective: To ascertain the effect of lacosamide on pain associated with peripheral diabetic neuropathy. Methods: One hundred nineteen patients with a 1 to 5-year history of pain attributed to diabetic neuropathy and a score of >= 4 on the Likert pain scale entered the multicenter, randomized, double-blind, placebo-controlled trial. Lacosamide (N = 60) titrated from 100 to 400 mg/d or maximum tolerated dose and placebo (N = 59) were the trial interventions. Primary efficacy criterion was change in pain score on the 11-point Likert pain scale. Secondary assessments included Short-Form McGill Pain and Short-Form-36 Quality of Life Questionnaires, sleep/ activity interference, pain intensity, Patient and Clinical Global Impression of Change, and Profile of Mood. Patients receiving at least I dose of medication underwent safety evaluation. Results: Ninety-four patients (lacosamide 46; placebo 48) completed the trial. Lacosamide had significantly (P = 0.039) better pain relief versus placebo (primary outcome). Improvements were also seen in secondary outcome measures. Adverse events occurred in 52 lacosamide and 44 placebo patients. Common adverse events, occurring in >= 5% of patients, were headache (lacosamide 18%, placebo 22%), dizziness (lacosamide 15%, placebo 8%), and nausea (lacosamide 12%, placebo 7%). Five lacosamide and 3 placebo patients withdrew for adverse events. Discussion: Lacosamide seems to attenuate pain in diabetic neuropathy in doses up to 400 mg/d and improves quality of life issues.