Department of Neurology, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
BACKGROUND: Postherpetic neuralgia (PHN) is a complication of shingles (herpes zoster), a painful rash due to varicella-zoster virus reactivation. Studies of patients with PHN and zoster sine herpete (radicular pain without rash) support the notion that low-grade viral ganglionitis contributes to pain. If chronic pain reflects active infection, then antiviral therapy may help patients with PHN. OBJECTIVE: To determine whether antiviral treatment helps reduce PHN-associated pain. DESIGN: Prospective, open-label phase I/II clinical trial. SETTING: Tertiary care university hospital. PATIENTS: Fifteen patients with moderate to severe PHN. INTERVENTIONS: Intravenous acyclovir at a dosage of 10 mg/kg every 8 hours for 14 days followed by oral valacyclovir at a dosage of 1000 mg 3 times per day for 1 month. MAIN OUTCOME MEASURE: Numeric Rating Scale for Pain score. RESULTS: As defined by a decrease of 2 or more points on the Numeric Rating Scale for Pain, 8 (53%) of 15 patients reported improvement. CONCLUSION: Clinical improvement reported by most of our patients warrants further investigation in a larger, randomized, double-blind, placebo-controlled trial.