Does treatment of acute herpes zoster prevent or shorten postherpetic neuralgia? A systematic review of the literature

OBJECTIVE - Our goal was to determine if any treatment of acute herpes zoster alters the incidence or duration of postherpetic neuralgia (PHN), a common sequela in elderly patients. SEARCH STRATEGY - We systematically searched MEDLINE and The Cochrane Library. We also examined the reference lists of identified trials and reviews. SELECTION CRITERIA - We included all randomized controlled trials of treatments of zoster published in English that included assessment of pain at any time after rash healing. DATA COLLECTION/ANALYSIS - Forty-two trials met inclusion criteria, and 2 reviewers independently evaluated them for methodologic quality and the statistical and clinical significance of results. MAIN RESULTS - Four placebo-controlled trials of oral acyclovir with 692 patients provided marginal evidence for reduction in pain incidence at 1 to 3 months following zoster onset. Famciclovir significantly reduced duration but not incidence of PHN in one placebo-controlled trial of 419 patients. Valacydovir significantly reduced duration but not incidence of PHN in one acyclovir-controlled trial of 1141 patients. Steroids had no effect on PHN. Amitriptyline for 90 days reduced pain incidence at 6 months in one placebo-controlled trial of 80 patients. A single trial of percutaneous electrical nerve stimulation (PENS) in 50 patients suggested a decrease in pain incidence at 3 and 6 months compared with famciclovir. CONCLUSIONS - There is limited evidence that current interventions prevent or shorten PHN. Famciclovir and valacyclovir have been shown to reduce the duration of PHN in single published trials. Well-designed and larger trials of amitriptyline and PENS should be conducted.