Acyclovir Dosing for Herpes Labialis
For herpes labialis (cold sores), the recommended oral acyclovir dosage is 800 mg five times daily for 7 days. 1
Oral Treatment Options
The European guidelines provide specific dosing recommendations for oral antiviral therapy for herpes infections:
- Acyclovir: 800 mg five times daily for 7 days
- Valacyclovir: 1000 mg three times daily for 7 days
- Famciclovir: 500 mg three times daily for 7 days
These dosages are intended to reduce the duration and severity of herpes labialis episodes 1.
Timing of Treatment
Treatment efficacy is maximized when initiated early:
- Start treatment at the first sign of prodrome (tingling, burning sensation)
- Early initiation significantly increases the likelihood of abortive lesions 2, 3
- Patient-initiated therapy within 1 hour of symptom onset shows better outcomes 3
Treatment Considerations
Topical vs. Oral Therapy
- Topical 5% acyclovir cream applied five times daily for 4-5 days can shorten healing time by approximately 1 day 4
- However, oral therapy appears more effective than topical formulations 5
- Topical therapy may be considered for mild cases or when oral therapy is contraindicated
Special Populations
Renal Impairment Dosing Adjustments:
| Creatinine Clearance (mL/min) | 800 mg Oral Dose Adjustment |
|---|---|
| >25 | 800 mg every 4 hours, 5x daily |
| 10-25 | 800 mg every 8 hours |
| <10 | 800 mg every 12 hours |
HIV-Infected Patients:
- Higher oral doses (400 mg orally 3-5 times daily) are recommended 1
- Closer monitoring for adverse effects is necessary
Children:
- For children under 45 kg: acyclovir 20 mg/kg body weight (maximum 800 mg/dose) orally 4 times daily for 7-10 days 1
Suppressive Therapy
For patients with frequent recurrences (typically >6 episodes per year), suppressive therapy may be considered:
- Acyclovir 400 mg twice daily
- Valacyclovir 500 mg daily
- Famciclovir 250 mg twice daily 1
Clinical Pearls
- Common Pitfall: Delaying treatment initiation significantly reduces efficacy. Patient education about early self-medication is crucial.
- Even with optimal treatment, acyclovir does not completely prevent the development of classical lesions but can reduce their duration 4.
- Pain management may include topical anesthetics and oral analgesics as needed 1.
- Treatment should continue for the full prescribed duration even if symptoms improve 1.