Acyclovir Tablet Dosage for Viral Eye Infections
For herpes simplex virus (HSV) ocular infections, oral acyclovir should be dosed at 400 mg five times daily for 7-10 days, though higher doses of 800 mg five times daily may be needed for severe or resistant cases. 1, 2
HSV Conjunctivitis and Keratitis
Standard oral dosing for HSV ocular disease is 200-400 mg five times daily, with the higher 400 mg dose demonstrating equivalent efficacy to topical antiviral therapy in clinical trials 1, 2. The 400 mg five times daily regimen achieves therapeutic tear film levels that exceed the mean in-vitro ID50 for HSV type 1 2.
- For HSV keratitis specifically, acyclovir 200-400 mg five times daily is the recommended oral regimen 1
- Treatment duration should be 7-10 days for acute episodes 1
- Higher doses (800 mg five times daily) should be considered for cases demonstrating resistance to standard therapy or in immunocompromised patients 1, 3
HSV Uveitis
For HSV uveitis flare-ups, valacyclovir 500 mg two to three times daily for 7-10 days is the preferred oral antiviral, as it provides superior bioavailability compared to acyclovir 4. However, when acyclovir tablets are used for uveitis, 200 mg orally five times daily has been studied, though this may be suboptimal 5.
Varicella Zoster Virus (VZV) Ocular Infections
For VZV conjunctivitis and keratitis in immunocompetent patients with persistent or recalcitrant disease, acyclovir 800 mg five times daily for 7 days is recommended 1.
Severe or Complicated Cases
For acute retinal necrosis (a sight-threatening viral retinitis), initial therapy requires intravenous acyclovir 10 mg/kg three times daily for 10-14 days, followed by oral therapy with either valacyclovir 1 g three times daily for 4-6 weeks or acyclovir 20 mg/kg for 4-6 weeks 1.
Critical Management Considerations
- Topical corticosteroids must be avoided in HSV epithelial infections as they potentiate viral replication, but may be used in conjunction with oral antivirals for HSV stromal keratitis 1, 4
- Follow-up within 1 week is essential, including visual acuity measurement and slit-lamp biomicroscopy 1, 4
- Oral antivirals alone may not adequately prevent progression of HSV blepharoconjunctivitis; adding topical antiviral treatment improves outcomes 1
- For patients not responding to standard acyclovir dosing after 5-7 days, increase to 800 mg five times daily before considering alternative agents 3
Long-term Prophylaxis
Lower doses of oral antivirals are used for long-term prophylaxis against recurrent HSV keratitis, though specific dosing should be adjusted based on clinical response 1, 4.