Acyclovir Pediatric Dosage Calculator

Calculates acyclovir dosing for HSV and VZV infections in children, including neonatal HSV.

kg

Current body weight in kilograms

months

Age in months

Clinical indication for acyclovir

⚠️ Warnings & Contraindications

  • Oral acyclovir bioavailability is approximately 12-20% in children
  • Neonates require IV therapy for disseminated or CNS HSV
  • Dose adjust for renal impairment
  • Monitor for neurotoxicity (altered mental status, tremors) with high-dose IV
  • HSV encephalitis requires 21 days of IV therapy

ℹ️ Clinical Notes

Oral suspension available as 200mg/5mL. IV dosing is weight-based. Neonatal dosing: 20 mg/kg/dose IV q8h. For VZV in older children, oral valacyclovir may be preferred due to better bioavailability.

References

  1. Acyclovir dosing in neonates and infants - pharmacokinetics - Antimicrobial Agents and Chemotherapy (2002)
  2. Drugs.com Acyclovir Dosage Guide - Drugs.com (2026)

Medical Disclaimer

This calculator is provided for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or calculated using this tool.

The authors and publishers of this calculator make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability, or availability of the information, products, services, or related graphics contained within this tool for any purpose.