What is the daily maintenance dose of valacyclovir (Valtrex) for suppressive therapy in genital herpes?

Valacyclovir Maintenance Dose for Genital Herpes Suppression

For immunocompetent patients with fewer than 10 recurrences per year, take valacyclovir 500 mg once daily; for those with 10 or more recurrences per year, take 1000 mg (1 gram) once daily. 1, 2

Dosing Algorithm by Patient Population

Immunocompetent Patients (Normal Immune Function)

Standard dosing based on recurrence frequency:

• Patients with ≤9 recurrences per year: 500 mg once daily 1, 3, 2
• Patients with ≥10 recurrences per year: 1000 mg (1 gram) once daily 1, 3, 2
  • Alternative: 250 mg twice daily (equally effective for frequent recurrences) 4

The CDC guidelines explicitly state that 500 mg once daily is less effective in patients with very frequent recurrences (≥10 episodes per year), making the higher dose critical for this subgroup 1.

HIV-Infected Patients

For HIV-infected patients with CD4+ count ≥100 cells/mm³:

• Required dose: 500 mg twice daily (not once daily) 1, 3, 2

This is a critical distinction—HIV-infected patients require twice-daily dosing even though immunocompetent patients can use once-daily regimens 3. Using once-daily dosing in HIV patients is inadequate 3.

Clinical Efficacy and Duration

• Daily suppressive therapy reduces recurrence frequency by ≥75% in patients with frequent outbreaks 1, 3
• Safety and efficacy documented for up to 1 year of continuous use with valacyclovir 1, 3
• Longer-term safety data exists for acyclovir (up to 6 years), but valacyclovir data is limited to 1 year 1

Reassessment Strategy

After 1 year of continuous suppressive therapy:

• Discuss discontinuation with the patient to reassess current recurrence frequency 1, 3
• Recurrences often decrease over time, potentially allowing therapy discontinuation 1
• This reassessment helps determine if continued suppression is still necessary 3

Renal Dosing Adjustments

For patients with impaired kidney function:

• CrCl 30-49 mL/min: No dose reduction needed for standard suppressive doses 1, 2
• CrCl 10-29 mL/min:
  • For 1 gram daily regimen: reduce to 500 mg every 24 hours 2
  • For 500 mg daily regimen: reduce to 500 mg every 48 hours 2
• CrCl <10 mL/min: Same as CrCl 10-29 mL/min 2
• Hemodialysis patients: Administer dose after dialysis session 2

No laboratory monitoring is required unless substantial renal impairment exists 1, 3.

Critical Safety Considerations

Important warnings to avoid:

• Do NOT use 8 grams per day in immunocompromised patients—this high dose has been associated with thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) in advanced HIV disease 1, 5
• Standard suppressive doses (500 mg to 1000 mg daily) have NOT been associated with TTP/HUS 3
• Advise adequate hydration to minimize nephrotoxicity risk 1

Treatment Failure Management

If recurrences persist despite appropriate suppressive therapy:

• Consider HSV resistance if lesions fail to resolve within 7-10 days 1, 3
• All acyclovir-resistant strains are also resistant to valacyclovir 1
• IV foscarnet (40 mg/kg every 8 hours) is the treatment of choice for resistant HSV 1, 3

Transmission Reduction

• Suppressive therapy reduces but does not eliminate asymptomatic viral shedding 1, 3
• For reduction of transmission to partners: 500 mg once daily is the FDA-approved dose 2
• Patients must be counseled that transmission can still occur even on suppressive therapy 3

Practical Administration

• Valacyclovir may be taken without regard to meals 2
• Once-daily dosing improves adherence compared to more frequent acyclovir regimens (which require twice-daily dosing) 3, 4
• The convenience of once-daily dosing is a key advantage for immunocompetent patients 6