The purpose of this study is to compare the safety and efficacy of Vacyless® and Valtrex® in patients with acute herpes zoster.

Primary Endpoint:

- Lesion assessment - Rash severity, in terms of rash counts

Secondary Endpoints:

• Pain assessment
• Clinical global impression
• Safety information of valacyclovir

Inclusion Criteria:

• Men and women between 20 to 80 years of age.
• Patients with a clinical diagnosis of HZ as evidenced by a unilateral dermatomal rash.
• Patients with zoster-related rash (rash severity is greater than or equal to mild).
• Patients are able to be enrolled into the study 72 hours from appearance of rash (for example, lesions or vesicles).
• Patients provided written informed consent.
• Patients who are able to complete all study visits per protocol.
• Men and premenopausal women must agree to practice a barrier method of birth control or the use of a spermicide for one month after the last dose of study drug (oral contraceptives are not permitted). Subject should be withdrew from the study if contraceptions are faild.

Exclusion Criteria:

• Women who are pregnant or lactating.
• Patients with multidermatomal or disseminated HZ (greater than 20 lesions beyond the dermatomes adjacent to the primarily involved dermatome).
• Patients with HZ ophthalmicus, defined as cutaneous lesions in the dermatome associated with the ophthalmic division of the trigeminal nerve
• Patients with history of impaired renal function, (e.g., calculated creatinine clearance less than 50 mL/min/1.73 m2)
• Patients are taking narcotic analgesic routinely for a chronic pain condition
• Patients are taking tricyclic antidepressants
• Patients who received systemic antivirals with activity against VZV within the past 30 days, or a topical antiviral to treat their current HZ
• Patients with immunosuppressive or immunodeficient condition resulting from:

disease (e.g., HIV) corticosteroid use (except intermittent or topical/inhaled beclomethasone dipropionate or equivalent < 800 mcg/day), or other immunosuppressive/cytotoxic therapy (cancer chemotherapy or organ transplantation )

• Patients with any other condition (e.g., extensive psoriasis, chronic pain syndrome, cognitive impairment) that, in the opinion of the site investigator, might interfere with the evaluations required by the study
• Patients who are not ambulatory (bed-ridden or homebound); hospitalized patients may be enrolled if they are ambulatory and able to complete the study requirements
• Patients with history of allergy to valacyclovir hydrochloride and acetaminophen
• Patients are unlikely to adhere to protocol follow-up