Reduction of Postherpetic Neuralgia in Herpes Zoster

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

Conditions
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Herpes Zoster, Post-herpetic Neuralgia

Intervention / Treatment
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* Drug: Gabapentin
* Drug: Valacyclovir


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Drug: Gabapentin|gabapentin 300mg/day, titrated up weekly to max tolerated dose or 3600mg/day (whichever is lower), for 4-9 weeks|
|Drug: Valacyclovir|valacyclovir 1000mg three-times daily x 7 days|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients with zoster pain at 6 months |  |  | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients with zoster pain at 4 months |  |  | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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gabapentin, valacyclovir, phn, shingles