This study is a 12-week randomized, double-blind, controlled multi-center evaluation of the efficacy, safety and tolerability of NGX-4010 for the treatment of PHN. Eligible subjects will have moderate to severe pain from PHN, with average NPRS scores during screening of 3 to 9 (inclusive). Painful areas of up to 1000 square centimeters will be treated during a single treatment administration in this study. Subjects will be randomly assigned to receive active NGX-4010 patches or low-concentration control patches that are identical in appearance, according to a 1:1 allocation scheme.~Subjects may be on stable chronic oral pain medication regimens, but currently will not be using any topical pain medications on the affected areas. NPRS scores for the average pain in the past 24 hours will be recorded daily in the evening, beginning on the day of the Screening Visit (usually on Day -14). Subjects will continue to record NPRS scores in a take-home diary from the evening on the day of treatment through the evening before the Termination Visit at Week 12. Subjects will return for interim follow-up visits at Weeks 4 and 8 following study treatment.
The purpose of the study is to assess the efficacy and safety of NGX-4010 applied for 60 minutes for the treatment of postherpetic neuralgia (PHN).