Safety and Efficacy of Gabapentin in Neuropathic Pain

Yoon, Duck Mi

Abstract

BACKGROUND
The newer generation of anticonvulsant, gabapentin is probably the most useful agent for neuropathic pain. This report reviews prospective safety and efficacy data collected in actual clinical situations for various neuropathic pains. METHODS: This was an open label, prospective, non-comparative, clinical study of gabapentin for the treatment of various neuropathic pain syndromes. 392 patients were enrolled between June, 2002 and August, 2003, and 42 pain specialists from 40 private pain clinics were participated in the study. Safety and efficacy were assessed in 177 patients after a minimum of 6 weeks of gabapentin treatment, with starting and final doses determined by the prescribing physician. The primary efficacy measure was a change in the average daily pain score (DPS) based on an 11-point Likert scale (0, no pain; 10, worst possible pain) and change in sleep interference (SI) from baseline to the final week of therapy. RESULTS: In 157 (88.7%) of the 177 patient gabapentin was assessed as effective, as follows; 72 patients (40.7%) were markedly improved; 85 patients (48.0%) moderately improved; 16 patients (9.0%) slightly improved; and 4 patients were unchanged. Patients that rated baseline pain as severe improved in 86.2 % (50/58 patients) of cases and 90% of patients that rated their baseline pain as mild to moderate showed improvement. Various neuropathic pains except other polyneuropathies, were clinically improved by more than 80%. Most patients were started at 300 mg/day of gabapentin, and were maintained within 600-900 mg/day at the end of the study. There was a significant reduction in the average daily pain score from 7.3 to 2.8 (P < 0.0001). Sleep Interference was also significantly improved from 5.0 to 1.6 points after gabapentin administration (P < 0.0001). Of the 392 patients, 58 patients (14.8%) experienced 67 adverse events (17.1%). Most events were mild but 6.0% were severe. CONCLUSIONS: Gabapentin is effective and safe drug for the treatment of neuropathic pain.