The addition of gabapentin therapy to standard antiviral treatment with valacyclovir in acute herpes zoster patients will decrease the incidence of post-herpetic neuralgia.

Inclusion Criteria:

• Male or female patients of 50 years of age and older.
• Patients with a clinical diagnosis of uncomplicated herpes zoster presenting within the first 72 hours of vesicles.
• Patients who are willing and able to comply with the requirements of the study.
• Patients who are willing and able to give written informed consent.
• Average pain score pre-therapy greater or equal than 4 on 10-point Likert scale.

Exclusion Criteria:

• Sexually-active women of childbearing potential, including postmenopausal women less than 1 year since last menses, not employing adequate contraception (approved oral contraceptive, intrauterine device, barrier methods or total abstinence).
• Pregnant females and nursing mothers.
• Patients with immune dysfunction including congenital immune deficiency, active malignancy of any type, collagen vascular diseases, organ or bone marrow transplantations, known infection with HIV or severe atopic dermatitis.
• Patients who have received cytotoxic drugs or immunosuppressive therapy (e.g., chronic systemic corticosteroids) within the previous 3 months.
• Patients with evidence of cutaneous or visceral dissemination of herpes zoster infection (cutaneous dissemination is defined as > 20 discrete lesions outside adjacent dermatomes).
• Patients who have received systemic anti-VZV medications or immunomodulatory medications (including interferon) within the previous 4 weeks.
• Patients currently receiving probenecid.
• Patients with impaired renal function: calculated creatinine clearance of <30 mL/min using Cockcroft and Gault formula.
• Patients with abnormal liver function (alanine transaminase (ALT) or aspartate;transaminase (AST) levels greater than five times the upper limit of the normal range).
• Patients with a history of intolerance or hypersensitivity to acyclovir, penciclovir, valacyclovir, famciclovir or gabapentin.
• Patients currently receiving therapy with gabapentin or tricyclic antidepressants.
• Patients with clinical evidence of ocular involvement of herpes zoster. Patients with herpes zoster of the ophthalmic branch of the trigeminal nerve without evidence of ocular involvement will be included.