Acyclovir Dosage for Shingles Treatment
The recommended dose of acyclovir for the treatment of shingles (herpes zoster) is 800 mg orally 5 times daily for 7 to 10 days. 1
Standard Dosing Regimen
The FDA-approved dosing regimen for acyclovir in the treatment of herpes zoster is:
- 800 mg orally every 4 hours, 5 times daily
- Duration: 7 to 10 days
- Treatment should be initiated as soon as possible, ideally within 72 hours of rash onset 2
This dosing regimen is supported by the Centers for Disease Control and Prevention (CDC) and the American College of Physicians, with a high strength of evidence 2.
Dosage Adjustments for Special Populations
Renal Impairment
Dosage adjustment is required for patients with renal impairment based on creatinine clearance 1:
| Creatinine Clearance (mL/min) | Adjusted Dosage |
|---|---|
| >25 | 800 mg every 4 hours, 5 times daily |
| 10-25 | 800 mg every 8 hours |
| 0-10 | 800 mg every 12 hours |
Pediatric Patients
For children under 45 kg, the CDC recommends:
- Acyclovir 20 mg/kg body weight (maximum 800 mg/dose) orally 4 times daily for 7-10 days 2
Immunocompromised Patients
- Immunocompromised patients may require longer treatment duration and closer monitoring 2
- For HIV-infected patients with shingles, higher doses may be required, especially with CD4+ counts <200 cells/µL 2, 3
- In severe cases or disseminated disease, IV acyclovir (10 mg/kg every 8 hours) may be indicated 2
Clinical Efficacy
Studies have demonstrated that oral acyclovir at 800 mg five times daily is effective for treating herpes zoster and is superior to lower doses (400 mg five times daily) 4. This higher dosage:
- Significantly shortens viral shedding period
- Accelerates lesion healing
- Reduces formation of new lesions
- Decreases duration and severity of acute pain
Treatment Considerations
- Treatment should begin as soon as possible after symptom onset, ideally within 72 hours of rash appearance 2
- Complete the full course of therapy even if symptoms improve before completion
- Monitor for complete resolution of lesions and evaluate for signs of dissemination or complications 2
- Patients should be scheduled for follow-up within 7 days to assess treatment response 2
Alternative Antiviral Options
While acyclovir is effective, newer antivirals may offer advantages in terms of dosing convenience:
- Valacyclovir (1,000 mg three times daily for 7 days) offers simpler dosing with similar efficacy 5
- Famciclovir (500 mg three times daily for 7 days) is also effective and may reduce the duration of postherpetic neuralgia 6, 7
However, acyclovir remains a standard first-line treatment option with extensive clinical experience and a well-established safety profile.