An Effectiveness and Safety Study With RWJ-333369 (Carisbamate) for the Study of Postherpetic Neuralgia (PHN).

Inclusion Criteria: * Diagnosis of postherpetic neuralgia (PHN) with a history of varicella-zoster rash (shingles), persistent pain for at least 6 months after the healing of the rash * Experienced postherpetic neuralgia pain on a daily basis for the past 3 months * Women must be postmenopausal for at least 2 years, sexually abstinent, or if sexually active, be practicing an effective method of birth control, and have a negative serum pregnancy test at screening. Exclusion Criteria: * History of a poor response to 3 or more medications for postherpetic neuralgia (PHN), with poor response defined as treatment with medications in the following categories of therapy for at least 1 month at therapeutic dosages without at least moderate improvement, as judged by the study doctor: Antiepileptic drugs, antidepressants, serotonin norepinephrine uptake inhibitors (SNRIs), opioid analgesics, or lidocaine patch * currently taking tricyclic antidepressants, Coumadin (warfarin), or continued treatment with an antiepileptic drug for any indication, Note: If taking these medications, to be eligible for the study, they must be tapered and discontinued * past neurolytic treatment (destruction of nerves by the application of chemicals, heat or cold, neurosurgery, intrathecal pumps, or spinal cord stimulators for PHN pain * currently using herbal topical creams or ointments for pain relief within 48 hours, capsaicin within 6 months, or systemic corticosteroids within 3 months of the baseline period * Prior exposure to RWJ-333369 (carisbamate).