Valacyclovir Use in Children
Valacyclovir can be used in children, but FDA approval is limited to specific age groups and conditions: it is approved for cold sores in children ≥12 years and for chickenpox in children 2 to <18 years. 1
FDA-Approved Indications for Valacyclovir in Children
- Cold sores (herpes labialis): Approved for children ≥12 years of age 1
- Chickenpox: Approved for children 2 to <18 years of age 1
- Recommended dosage: 20 mg/kg three times daily for 5 days (not to exceed 1 gram three times daily) 1
Non-FDA Approved Uses
Valacyclovir is not FDA-approved for the following pediatric populations:
- Children <12 years with cold sores
- Children <18 years with genital herpes
- Children <18 years with herpes zoster
- Children <2 years with chickenpox
- Suppressive therapy following neonatal HSV infection 1
Pharmacokinetics in Children
- In children 3 months to <6 years, a 25 mg/kg dose provides comparable systemic acyclovir exposures to a 1-gram dose in adults 1
- In infants 1 month to <3 months, a 25 mg/kg dose results in higher exposures (Cmax: ↑30%, AUC: ↑60%) than a 1-gram dose in adults 1
- Dose proportionality exists across the 10 to 20 mg/kg valacyclovir dose range in children 2
- The relative bioavailability of valacyclovir tablets compared to suspension is approximately 115% 3
Safety Considerations
- Valacyclovir is generally well-tolerated in pediatric patients 2, 4
- Most common adverse effects are gastrointestinal disturbances and headache, occurring in a small number of subjects 3
- Renal function should be monitored, especially with prolonged courses, as dose adjustment is necessary for patients with renal impairment 1
- Maintaining adequate hydration is important to reduce the risk of nephropathy 5
Clinical Recommendations Based on Age
Children <3 months
- Not recommended due to decreased clearance in this age group 2
Children 3 months to <2 years
- Not FDA-approved for any indication 1
- Limited pharmacokinetic data available, but no efficacy data to support use 1
Children 2 to <12 years
- Approved for chickenpox only: 20 mg/kg three times daily for 5 days (maximum 1 gram three times daily) 1
- For HSV infections (off-label): CDC guidelines suggest acyclovir 20 mg/kg (max 400 mg/dose) three times daily for 5-10 days for mild gingivostomatitis 6, 5
Children ≥12 years
- Approved for cold sores 1
- For mucocutaneous HSV infections: 1 gram twice daily for 7-10 days (off-label dosing based on adult recommendations) 5
Important Clinical Considerations
- Valacyclovir provides enhanced bioavailability compared to acyclovir, achieving higher serum concentrations 4
- Treatment should be initiated as early as possible in the disease course, ideally within 24 hours of symptom onset for maximum effectiveness 7, 8
- For severe cases, initial treatment with intravenous acyclovir is recommended, followed by transition to oral therapy once clinical improvement is evident 5
Conclusion
While valacyclovir has FDA-approved indications for children in specific age groups and conditions, its use should be limited to these approved indications or carefully considered for off-label use based on pharmacokinetic data and clinical experience. For most pediatric HSV infections outside the approved indications, acyclovir remains the standard first-line therapy.