The purpose of this Study is to test the Safety and Effectiveness of MK0686 in relieving neuropathic (chronic) pain as experienced by patients with Postherpetic Neuralgia (Also Know as PHN or Post Shingles Pain).

This is an early phase trial and some specific protocol information is proprietary and not publicly available at this time. (Full information is available to trial participants).

Inclusion Criteria:

• Diagnosis of postherpetic neuralgia with pain having lasted at least 6 months
• Able to complete study questionnaires, patient diary, and comply with daily study medication
• Patient is not satisfied with current treatment for pain control

Exclusion Criteria:

• Pregnant or nursing female
• History of evidence of a condition that in the opinion of the investigator, may interfere with the study results (e.g., diabetic neuropathy of fibromyalgia) or pose undue risk to undergo the course of medication required by the study (e.g., unstable heart disease, morbid obesity, kidney or liver disease)