This study is a 12-week multicenter randomized, double-blind, controlled evaluation of the efficacy, safety and tolerability of NGX-1998 for the treatment of postherpetic neuralgia (PHN). Eligible subjects will have pain from PHN, with average numeric pain rating scale (NPRS) scores during screening of 4 to 9 (inclusive). Painful areas of up to 1500 cm2 will be treated during a single Test Article application. Subjects will be randomly assigned to receive NGX-1998 (10% or 20% w/w) or placebo according to an unequal allocation scheme of 2:2:1. Subjects will also be stratified by gender.
The purpose of this study is to assess the efficacy, safety and tolerability of NGX-1998 applied for 5 minutes for the treatment of postherpetic neuralgia (PHN).