 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. 