Improvement of postherpetic neuralgia after treatment with intravenous acyclovir followed by oral valacyclovir

Abstract

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.