Acyclovir Prophylactic Dosing for BSA 1.1 m²
For a child with BSA 1.1 m², the prophylactic acyclovir dose is 550 mg IV every 8 hours (500 mg/m² × 1.1 m² = 550 mg per dose), administered three times daily. 1
Dosing Algorithm Based on BSA
The CDC guidelines specifically recommend BSA-based dosing for IV acyclovir prophylaxis in children over 1 year of age:
- Standard prophylactic dose: 500 mg/m²/dose IV every 8 hours 1
- For BSA 1.1 m²: 500 mg/m² × 1.1 = 550 mg per dose
- Frequency: Three times daily (every 8 hours) 1
This BSA-based approach is explicitly stated in the CDC/NIH guidelines as an alternative to weight-based dosing for children aged >1 year, particularly in the context of preventing opportunistic infections in immunocompromised patients 1.
Clinical Context and Indications
This prophylactic dosing regimen applies primarily to:
- HIV-infected or immunocompromised children requiring herpes simplex virus (HSV) or varicella zoster virus (VZV) prophylaxis 1
- Children undergoing bone marrow transplantation or other significant immunosuppression 2
- Prevention of viral reactivation during periods of severe immunosuppression 1
Important Caveats
Renal function monitoring is essential - acyclovir is cleared almost entirely by the renal route, and dosage adjustment is required in patients with renal impairment 3, 4. The primary adverse effect is crystalluria and elevated serum creatinine, particularly with bolus IV administration 3.
Hydration requirements - ensure adequate hydration throughout treatment to prevent crystalluria 5. Infuse over 1-2 hours rather than as a bolus 1.
Age consideration - this BSA-based dosing is specifically recommended for children >1 year of age 1. For neonates and younger infants, weight-based dosing may be more appropriate.
Prophylaxis does not eradicate latent virus - acyclovir suppresses viral reactivation during administration but does not eliminate latency 6, 3. Recurrent infections are common after discontinuation 2.