Efficacy, safety, and tolerability of pregabalin treatment for painful diabetic peripheral neuropathy - Findings from seven randomized, controlled trials across a range of doses

OBJECTIVE - To evaluate the efficacy, safety, and tolerability of pregabalin across the effective dosing range, to determine differences in the efficacy of three times daily (TID) versus twice daily (BID) dosage schedules, and to use time-to-event analysis to determine the time to onset of a sustained therapeutic effect using data from seven trials of pregabalin in painful diabetic peripheral neuropathy (DPN). RESEARCH DESIGN AND METHODS - Data were pooled across seven double-blind, randomized, placebo-controlled trials using pregabalin to treat painful DPN with dosages of 150, 300, and 600 mg/day administered TID or BID. Only one trial included all three of these dosages, and TID dosing was used in four. All studies shared fundamental selection criteria, and treatment durations ranged from 5 to 13 weeks. RESULTS - Pooled analysis showed that pregabalin significantly reduced pain and painrelated sleep interference associated with DPN (150, 300, and 600 mg/day administered TID vs. placebo, all P <= 0.007). Only the 600 mg/day dosage showed efficacy when administered BID (P <= 0.001). Pain and sleep interference reductions associated with pregabalin appear to be positively correlated with dosage; the greatest effect was observed in patients treated with 600 mg/day. Kaplan-Meier analysis revealed that the median time to onset of a sustained (>= 30% at end point) I-point improvement was 4 days in patients treated with pregabalin at 600 mg/day, 5 days in patients treated with pregabalin at 300 mg/day, 13 days in patients treated with pregabalin at 150 mg/day, and 60 days in patients receiving placebo. The most common treatment-emergent adverse events were dizziness, somnolence, and peripheral edema. CONCLUSIONS - Treatment with pregabalin across its effective dosing range is associated with significant, dose-related improvement in pain in patients with DPN.