Herpes zoster (commonly referred to as "shingles") results from the reactivation of the varicella-zoster virus acquired during a primary infection, usually chickenpox. The virus lays dormant in the cells of the nerves until activated. Once activated, patients develop a characteristic red blistering rash which crusts and heals in 2 - 4 weeks. Postherpetic neuralgia (PHN), the term for pain persisting after the herpes zoster (HZ) eruption heals, is the most common and most feared complication of herpes zoster infection. The drug, Civamide is thought to desensitize the nerves and decrease the pain of PHN. This is the pharmacologic rationale for its use in the nose in postherpetic neuralgia of the trigeminal nerve, a nerve that is in the nose and transmits pain from the face. The objective of this study is to evaluate the safety and efficacy of intranasally administered Civamide (0.01%) for the treatment of moderate to severe daily pain associated with postherpetic neuralgia of the trigeminal nerve. Neuropathic pain must have persisted for ≥ 12 months.