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.