PROTOCOL OUTLINE:

This is a randomized, double blind study.

Patients are randomized to one of two treatment arms.

Arm I: Patients receive standard dose oral valacyclovir three times a day on Days 1-7.

Arm II: Patients receive higher dose oral valacyclovir three times a day on Days 1-7.

Both arms: Patients begin treatment within 72 hours after onset of zoster rash.

Quality of life is assessed on Days 1, 14, and 28 during study and then every 4 weeks through Week 24. Pain is assessed on Days 1-28 during study, and then weekly through Week 24. Medical resource utilization is assessed on Days 1, 8, 14, and 18 during study and then every 4 weeks through Week 24.

Patients are followed every 4 weeks through Week 24.

PROTOCOL ENTRY CRITERIA:

--Disease Characteristics--

Patients with a clinical diagnosis of uncomplicated herpes zoster presenting within 72 hours after onset of zoster rash

No evidence of cutaneous or visceral dissemination of herpes zoster infection; cutaneous dissemination defined as at least 20 discrete lesions outside adjacent dermatomes

Must have immune dysfunction caused by any of the following: congenital immune deficiency; active malignancy of any type; collagen vascular diseases; organ or bone marrow transplantation; HIV infection; severe atopic dermatitis; received cytotoxic drugs or immunosuppressive therapy (e.g., chronic systemic corticosteroids) within past 3 months

CD4 count at least 50%

--Prior/Concurrent Therapy--

Biologic therapy: Greater than 9 months since prior bone marrow transplantation

Surgery: Greater than 9 months since prior liver or heart transplantation

Other: At least 4 weeks since prior topical or systemic anti-varicella zoster virus (anti-VZV) medications; no concurrent systemic agents with anti-VZV activity from enrollment to Day 10; no concurrent probenecid from 24 hours before the first dose of study drug until Day 10

--Patient Characteristics--

Hepatic: AST or ALT no greater than 5 times upper limit of normal

Renal: Creatinine clearance at least 30 mL/min

Other: Not pregnant or nursing; negative pregnancy test; fertile patients must use effective contraception; no history of intolerance or hypersensitivity to acyclovir, penciclovir, valacyclovir, or famciclovir