Valacyclovir Dosing for Herpes Simplex Keratitis
For acute treatment of HSV keratitis, valacyclovir (Valtrex) should be dosed at 500 mg two or three times per day, combined with topical antiviral therapy for optimal outcomes. 1
Acute Treatment Regimen
- Standard dose: Valacyclovir 500 mg orally 2-3 times daily 1
- Duration: Continue until epithelial healing is complete, typically 7-14 days 1
- Combination therapy required: Oral antivirals alone are inadequate for HSV keratitis—must add topical antiviral therapy (ganciclovir 0.15% gel 3-5 times daily OR trifluridine 1% solution 5-8 times daily) 1
The American Academy of Ophthalmology guidelines consistently emphasize that oral antivirals by themselves may not prevent progression of HSV blepharoconjunctivitis or keratitis, making the addition of topical therapy essential for corneal involvement 1.
Treatment-Resistant Cases
- Higher doses: If standard therapy fails, anecdotal experience supports using higher doses of oral antivirals, though specific dosing is not standardized 1
- Alternative agent: Oral valganciclovir 900 mg twice daily for 10 days (treatment dose) may be effective in patients unresponsive or allergic to conventional antivirals 2
Long-Term Prophylaxis
- Prophylactic dose: Lower doses than acute treatment are used for preventing recurrent HSV keratitis 1
- Specific prophylactic regimen: While guidelines mention "lower doses," research supports 300-400 mg daily for long-term prophylaxis 3, 4
- Duration: Prophylaxis may be continued for 1 year or longer in patients with frequent recurrences 3, 4
Critical Clinical Considerations
Topical therapy selection: Prefer ganciclovir 0.15% gel over trifluridine because trifluridine inevitably causes epithelial toxicity if used beyond 2 weeks 1
Avoid corticosteroids: Topical corticosteroids potentiate HSV epithelial infections and must be avoided during active epithelial disease 1
Renal dosing: Exercise caution in patients with impaired renal clearance, as valacyclovir requires dose adjustment 1
Follow-up timing: Re-evaluate within 1 week with visual acuity measurement and slit-lamp biomicroscopy to assess epithelial healing 1
Alternative Oral Antivirals
If valacyclovir is unavailable or contraindicated:
- Acyclovir: 200-400 mg orally 5 times daily (less convenient dosing) 1
- Famciclovir: 250 mg orally twice daily 1
The 2024 American Academy of Ophthalmology Conjunctivitis Preferred Practice Pattern represents the most current guideline evidence, consistently recommending the 500 mg 2-3 times daily dosing across multiple iterations 1.