This eight-month study is evaluating the efficacy of two doses of this new medication compared to placebo in lowering pain intensity in patients with PHN.

Major Inclusion/Exclusion Criteria:

• Ages 18-80
• Persistent PHN pain for a minimum of 9 months following a the onset of a herpes zoster skin rash (shingles)
• Must be on only one chronic pain drug, and must be willing to stay on that drug maintaining that stable dose for the duration of the study
• Must not have any other neuropathic pain