For a neonate weighing 4 kg, what is the recommended acyclovir dose per kilogram per dose every 8 hours?

• A. 10 mg/kg every 12 hours
• B. 20 mg/kg every 8 hours
• C. 40 mg/kg every 8 hours
• D. 30 mg/kg every 6 hours

Answer: (D)

Neonatal acyclovir dosing is weight-based and given in divided doses to reach an effective daily exposure while protecting renal function. For neonates with HSV infection and normal renal function, the standard total daily dose is about 60 mg/kg, split into three equal doses every 8 hours. That translates to 20 mg/kg per dose every 8 hours.

For a 4 kg neonate, each dose would be 20 mg/kg × 4 kg = 80 mg, given every 8 hours. The per-kilogram per-dose figures align with this: the typical per-dose amount is 20 mg/kg every 8 hours, not 10 mg/kg q12h, 40 mg/kg q8h, or 30 mg/kg q6h, which would push the daily total outside the recommended range. In practice, adjust if renal function is reduced.