What is the recommended acyclovir (antiviral medication) maintenance therapy regimen for herpes and what laboratory tests, such as complete blood counts (CBC) and renal function tests, should be ordered to monitor for potential side effects?

Acyclovir Maintenance Therapy for Herpes and Laboratory Monitoring

For suppressive therapy of recurrent genital herpes, acyclovir 400 mg orally twice daily is the recommended maintenance regimen, with routine monitoring of renal function tests recommended before initiation and periodically during long-term therapy. 1, 2

Maintenance Therapy Regimens

Standard Suppressive Therapy

• First-line regimen: Acyclovir 400 mg orally twice daily 1, 2
• Alternative regimen: Acyclovir 200 mg orally 3-5 times daily 1

The standard suppressive therapy is indicated for patients with frequent recurrences (six or more episodes per year). This regimen reduces recurrences by at least 75% in most patients 1.

Duration of Therapy

• Initial course: Up to 12 months 2
• After 1 year: Discontinue therapy temporarily to reassess recurrence frequency 1
• Safety has been documented for up to 6 years of continuous therapy 1

Laboratory Monitoring

Before Initiating Therapy

• Baseline renal function tests: BUN, serum creatinine, and creatinine clearance
  • Critical because acyclovir is eliminated primarily by the kidneys 3

During Maintenance Therapy

• Renal function tests: Every 6-12 months during long-term therapy
• Dosage adjustment required for renal impairment according to creatinine clearance 2:
  • CrCl >10 mL/min: 400 mg every 12 hours
  • CrCl 0-10 mL/min: 200 mg every 12 hours

Not Routinely Required

• Complete blood count (CBC) monitoring is not routinely recommended for standard maintenance therapy in immunocompetent patients
• Liver function tests are not routinely required

Special Considerations

Immunocompromised Patients

• Higher dosages may be required: 400 mg orally 3-5 times daily 1
• For HIV-infected patients with recurrent herpes 4:
  • Initial treatment: 400 mg five times daily until eruption clears
  • Initial maintenance: 400 mg three times daily for 1-2 months
  • Long-term maintenance: 400 mg twice daily

Monitoring for Drug Resistance

• Resistance is rare in immunocompetent patients on suppressive therapy 1
• Consider resistance if lesions persist despite appropriate therapy, particularly in immunocompromised patients 1

Common Pitfalls to Avoid

1. Failure to adjust dosage for renal impairment: Always check renal function and adjust dosing accordingly 2

2. Indefinite continuation without reassessment: After 1 year, temporarily discontinue therapy to reassess recurrence frequency, as some patients experience decreased frequency over time 1

3. Inadequate patient counseling: Inform patients that:

   • Suppressive therapy reduces but does not eliminate asymptomatic viral shedding and transmission risk 1
   • Condom use is still recommended during sexual activity 1
   • Medication should be taken consistently for maximum effectiveness 5

4. Missing breakthrough episodes: Even with suppressive therapy, some patients (approximately 4%) may experience breakthrough episodes requiring episodic treatment 4

Acyclovir maintenance therapy is highly effective and well-tolerated for long-term management of recurrent genital herpes, with minimal laboratory monitoring requirements focusing primarily on renal function.