General

• Dose should be decreased in patients with impaired renal function.
• Oral dosage of acyclovir in children should not exceed 80 mg/kg per day.
• Acyclovir doses listed below are based on clinical trials and clinical experience and may not be identical to doses approved by the US Food and Drug Administration.

Neonatal herpes simplex virus (HSV) infection

• Birth–3 mo: 60 mg/kg IV per day in 3 divided doses for 14–21 days

HSV encephalitis

• ≥3 mo–12 yr: 60 mg/kg IV per day in 3 divided doses for 14–21 days
• ≥12 yr: 30 mg/kg IV per day in 3 divided doses for 14–21 days

Varicella in immunocompetent host

• ≥2 yr
  • 80 mg/kg PO per day in 4 divided doses for 5 days; maximum dose, 3200 mg/day
  • 30 mg/kg IV per day for 7–10 days, or 1500 mg/m² IV per day in 3 doses for 7–10 days

Varicella in immunocompromised host

• < 1 yr: 30 mg/kg IV per day in 3 divided doses for 7–10 days
• ≥1 yr: 1500 mg/m² IV of body surface area per day in 3 divided doses for 7–10 days; some experts recommend the 30-mg/kg per day IV dose

Zoster in immunocompetent host

• Intravenous
  • < 1 yr: 30 mg/kg IV per day in 3 divided doses for 7–10 days
  • ≥1 yr: 1500 mg/m² IV of body surface area per day in 3 divided doses for 7–10 days; some experts recommend the 30-mg/kg per day IV dose
• Oral
  
  • ≥12 yr: 4000 mg/day in 5 divided doses for 5–7 days

Herpes-zoster in immunocompromised host

• < 12 yr: 60 mg/kg IV per day, every 8 hr, for 7–10 days
• ≥12 yr: 30 mg/kg IV per day, every 8 hr, for 7 days

HSV infection in immunocompromised host (localized, progressive, or disseminated)

• Intravenous
  
  • < 12 yr: 30 mg/kg per day in 3 divided doses for 7–14 days
  • ≥12 yr: 15 mg/kg per day in 3 divided doses for 7–14 days

• Oral
  
  • ≥2 yr 1000 mg/day in 3-5 divided doses for 7–14 days

Prophylaxis of HSV in immunocompromised host

• ≥2 yr: 600–1000 mg/day PO in 3–5 divided doses during period of risk

HSV-seropositive patients

• All ages: 15 mg/kg IV in 3 divided doses during period of risk

Genital HSV infection: first episode

• Oral
  
  • Oral pediatric dose (≤12 yr): 40–80 mg/kg per day divided in 3–4 doses for 5–10 days (maximum, 1.0 g/day)
  • ≥12 yr: 1000–1200 mg/day in 3–5 divided doses for 7–10 days

• IV
  
  • ≥12 yr: 15 mg/kg per day in 3 divided doses for 5–7 days

Genital HSV infection: recurrence

• ≥12 yr: 1000–1200 mg/day PO in 3 divided doses for 3–5 days

Chronic suppressive therapy for recurrent genital and cutaneous (ocular) HSV episodes

• ≥12 yr: 800–1200 mg/day PO in 2 divided doses for up to 12 continuous months