Time to Onset of Neuropathic Pain Reduction: A Retrospective Analysis of Data From Nine Controlled Trials of Pregabalin for Painful Diabetic Peripheral Neuropathy and Postherpetic Neuralgia

These retrospective analyses of daily mean pain scores from nine placebo-controlled trials of pregabalin at 150, 300, or 600 mg/day (pregabalin, n = 1205; placebo, n = 772) examined time to significant reduction of pain during the first 2 weeks of treatment of painful diabetic peripheral neuropathy and postherpetic neuralgia. Time to onset of reduction in pain-defined as the first day for which patients treated with pregabalin had significant reductions (P < 0.05) in mean pain score compared with the placebo group for that day and the subsequent day-was calculated for all treatment groups demonstrating statistically significant reduction in pain at trial end point. The time to a 1-point or greater improvement in mean pain score was measured for each patient who was a responder at end point (30% or greater improvement in mean pain score). In seven of the nine trials (representing 11 of 14 pregabalin arms), significant reduction in pain was achieved at end point. The time to onset for reduction in pain was treatment Day 1 or 2 in nine of these successful treatment arms. Individual responder analysis confirmed that responders in the pregabalin groups reported a 1-point or greater pain reduction earlier than responders in placebo groups (P < 0.0001). However, this analysis is not a direct estimate of the likelihood that an individual patient would experience noticeable pain relief by the end of the second day. Overall, for patients who will respond to pregabalin, statistically significant and sustained reduction of pain associated with diabetic peripheral neuropathy and posttherapeutic neuralgia occurs early, usually by the end of 2 days of pregabalin treatment.