Acyclovir Dosing for Genital Herpes Suppression
The recommended dosing for acyclovir for genital herpes suppression is 400 mg orally twice daily for up to 12 months, followed by re-evaluation. 1
Primary Dosing Recommendations
The FDA-approved dosing for chronic suppressive therapy of recurrent genital herpes with acyclovir is:
- First-line regimen: 400 mg orally twice daily for up to 12 months 1
- Alternative regimens: Doses ranging from 200 mg 3 times daily to 200 mg 5 times daily 1
After 1 year of suppressive therapy, patients should be re-evaluated to assess the need for continued treatment based on the frequency and severity of recurrences 1.
Dosing Based on Recurrence Frequency
The Centers for Disease Control and Prevention (CDC) recommends the following for daily suppressive therapy:
- For patients with frequent recurrences (six or more per year), suppressive therapy reduces the frequency of HSV recurrences by at least 75% 2
- Suppressive treatment with oral acyclovir does not completely eliminate viral shedding or transmission risk 2
Efficacy and Duration
- Long-term studies have documented safety and efficacy for patients receiving daily suppressive therapy for as long as 5 years 2
- Clinical trials have shown that suppressive therapy reduces recurrence frequency from a mean of 1.1 per 28 days before treatment to 0.11 during treatment 3
- After discontinuation of suppressive therapy, the frequency of recurrences may remain lower than pre-treatment levels, but most patients will experience recurrences within 1-4 weeks 4
Dosage Adjustments for Renal Impairment
For patients with renal impairment, acyclovir dosage should be modified as follows 1:
| Creatinine Clearance (mL/min) | Dose 400 mg | Dosing Interval |
|---|---|---|
| >10 | 400 mg | every 12 hours |
| 0-10 | 200 mg | every 12 hours |
Special Populations
- HIV-infected patients: Higher oral doses may be required, especially with CD4+ counts <200 cells/µL 5
- Hemodialysis patients: An additional dose should be administered after each dialysis session 1
- Peritoneal dialysis: No supplemental dose appears necessary after adjustment of the dosing interval 1
Clinical Considerations
- Suppressive therapy reduces asymptomatic viral shedding, which may reduce transmission risk, though it does not completely eliminate this risk 2
- After 1 year of continuous suppressive therapy, acyclovir should be discontinued to reassess the patient's recurrence rate 2
- For patients who develop breakthrough episodes while on suppressive therapy, episodic treatment with acyclovir 200 mg orally 5 times daily for 5 days can be used 6
Common Pitfalls to Avoid
- Inadequate duration: Suppressive therapy should be continued for up to 12 months before re-evaluation
- Failure to adjust for renal function: Acyclovir is primarily eliminated by the kidneys, so dosage adjustment is critical in patients with renal impairment
- Missing the opportunity for re-evaluation: After 1 year of therapy, patients should be re-evaluated to determine if continued suppressive therapy is necessary
- Overlooking drug resistance: Although rare in immunocompetent patients, acyclovir-resistant HSV strains can develop in patients on long-term therapy 2