This medication is an antiviral agent, prescribed for herpes simplex, genital herpes, herpes zoster and chickenpox. It slows down the growth and spread of the herpes virus. Acyclovir is also sometimes used to treat eczema herpeticum, herpes infections of the skin, eyes, nose, and mouth in patients with human immunodeficiency virus (HIV) . (Dosage) : Acute Treatment of Herpes Zoster: 800 mg every 4 hours orally, 5 times daily for 7 to 10 days. Genital Herpes: Treatment of Initial Genital Herpes: 200 mg every 4 hours, 5 times daily for 10 days. Chronic Suppressive Therapy for Recurrent Disease: 400 mg 2 times daily for up to 12 months, followed by re-evaluation. Treatment of Chickenpox: Children (2 years of age and older): 20 mg/kg per dose orally 4 times daily (80 mg/kg/day) for 5 days. Adults and Children over 40 kg: 800 mg 4 times daily for 5 days.