DOSAGE AND ADMINISTRATION CAUTION - RAPID OR BOLUS INTRAVENOUS INJECTION MUST BE AVOIDED (see WARNINGS and PRECAUTIONS ). INTRAMUSCULAR OR SUBCUTANEOUS INJECTION MUST BE AVOIDED (see WARNINGS ). Therapy should be initiated as early as possible following onset of signs and symptoms of herpes infections. A maximum dose equivalent to 20 mg/kg every 8 hours should not be exceeded for any patient. Dosage HERPES SIMPLEX INFECTIONS MUCOSAL AND CUTANEOUS HERPES SIMPLEX (HSV-1 AND HSV-2) INFECTIONS IN IMMUNOCOMPROMISED PATIENTS Adults and Adolescents (12 years of age and older) 5 mg/kg infused at a constant rate over 1 hour, every 8 hours for 7 days. Pediatrics (Under 12 years of age) 10 mg/kg infused at a constant rate over 1 hour, every 8 hours for 7 days. SEVERE INITIAL CLINICAL EPISODES OF HERPES GENITALIS Adults and Adolescents (12 years of age and older) 5 mg/kg infused at a constant rate over 1 hour, every 8 hours for 5 days. HERPES SIMPLEX ENCEPHALITIS Adults and Adolescents (12 years of age and older) 10 mg/kg infused at a constant rate over 1 hour, every 8 hours for 10 days. Pediatrics (3 months to 12 years of age) 20 mg/kg infused at a constant rate over 1 hour, every 8 hours for 10 days . Neonatal Herpes Simplex Virus Infections (Birth to 3 months) 10 mg/kg infused at a constant rate over 1 hour, every 8 hours for 10 days. In neonatal herpes simplex infections, doses of 15 mg/kg or 20 mg/kg (infused at a constant rate over 1 hour every 8 hours) have been used; the safety and efficacy of these doses are not known. VARICELLA-ZOSTER INFECTIONS ZOSTER IN IMMUNOCOMPROMISED PATIENTS Adults and Adolescents (12 years of age and older) 10 mg/kg infused at a constant rate over 1 hour, every 8 hours for 7 days. Pediatrics (Under 12 years of age) 20 mg/kg infused at a constant rate over 1 hour, every 8 hours for 7 days. Obese Patients Obese patients should be dosed at the recommended adult dose using Ideal Body Weight. PATIENTS WITH ACUTE OR CHRONIC RENAL IMPAIRMENT Refer to DOSAGE AND ADMINISTRATION section for recommended doses, and adjust the dosing interval as indicated in Table 5. Table 5: Dosage Adjustments for Patients with Renal Impairment Creatinine Clearance (mL/min/1.73 m 2 ) Percent of Recommended Dose Dosing Interval (hours) >50 100% 8 25 to 50 100% 12 10 to 25 100% 24 0 to 10 50% 24 Hemodialysis For patients who require dialysis, the mean plasma half-life of acyclovir during hemodialysis is approximately 5 hours. This results in a 60% decrease in plasma concentrations following a six-hour dialysis period. Therefore, the patient’s dosing schedule should be adjusted so that an additional dose is administered after each dialysis. Peritoneal Dialysis No supplemental dose appears to be necessary after adjustment of the dosing interval. Administration The calculated dose should be further diluted in an appropriate intravenous solution at a volume selected for administration during each 1 hour infusion. Infusion concentrations of approximately 7 mg/mL or lower are recommended. In clinical studies, the average 70 kg adult received between 60 and 150 mL of fluid per dose. Higher concentrations (e.g., 10 mg/mL) may produce phlebitis or inflammation at the injection site upon inadvertent extravasation. Standard, commercially available electrolyte and glucose solutions are suitable for intravenous administration; biologic or colloidal fluids (e.g., blood products, protein solutions, etc.) are not recommended. Once diluted for administration, each dose should be used within 24 hours. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.