What is the recommended daily dose of valacyclovir (Valtrex) for treating herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections?

Valacyclovir Daily Dosing

The recommended daily dose of valacyclovir varies by indication: 500 mg once daily for genital herpes suppression, 1000 mg three times daily for herpes zoster, 1000 mg twice daily for acute genital herpes episodes, and 2000 mg twice daily (single day) for cold sores. 1

Genital Herpes (HSV)

Initial Episode

• 1000 mg twice daily for 10 days 1
• Most effective when initiated within 48 hours of symptom onset 1

Recurrent Episodes

• 500 mg twice daily for 3 days 1
• Initiate at first sign or symptom of recurrence 1

Suppressive Therapy (Immunocompetent)

• 1000 mg once daily for patients with normal immune function 1
• Alternative: 500 mg once daily for patients with ≤9 recurrences per year 1, 2
• Once-daily dosing prevents or delays 85% of recurrences compared to placebo 2

Suppressive Therapy (HIV-Infected)

• 500 mg twice daily for patients with CD4+ count ≥100 cells/mm³ 1
• This regimen demonstrated similar efficacy to acyclovir 400 mg twice daily in HIV-positive patients 3

Transmission Reduction

• 500 mg once daily for the source partner with ≤9 recurrences per year 1
• Reduces symptomatic HSV-2 acquisition by 75% in susceptible partners 1

Herpes Zoster (Shingles)

Standard Dosing

• 1000 mg three times daily for 7 days 1
• Therapy should be initiated within 48 hours of rash onset 1
• This regimen significantly reduces duration of zoster-associated pain compared to acyclovir 4

Alternative Dosing for Enhanced Compliance

• 1500 mg twice daily for 7 days is equally safe and effective as three times daily dosing 5
• Twice-daily regimen may improve patient adherence 5

Persistent or Recalcitrant Disease

• 1000 mg every 8 hours for 7 days for immunocompetent patients with persistent disease 6

Cold Sores (Herpes Labialis)

• 2000 mg twice daily for 1 day (doses taken 12 hours apart) 1
• Initiate at earliest symptom (tingling, itching, burning) 1
• Approved for patients ≥12 years of age 1

Chickenpox (Varicella)

Pediatric Dosing (Ages 2 to <18 years)

• 20 mg/kg three times daily for 5 days 1
• Maximum dose: 1000 mg three times daily 1
• Initiate at earliest sign or symptom 1

Acute Retinal Necrosis (Severe VZV/HSV)

• Initial: Acyclovir 10 mg/kg IV three times daily for 10-14 days 7, 8
• Followed by: Valacyclovir 1000 mg three times daily for 4-6 weeks (for patients able to receive adult dosing) 7, 8

Renal Impairment Adjustments

Creatinine Clearance 30-49 mL/min

• Herpes zoster: 1000 mg every 12 hours 1
• Genital herpes suppression: No reduction needed 1
• Recurrent genital herpes: No reduction needed 1

Creatinine Clearance 10-29 mL/min

• Herpes zoster: 1000 mg every 24 hours 1
• Genital herpes suppression: 500 mg every 24 hours 1
• Recurrent genital herpes: 500 mg every 24 hours 1

Creatinine Clearance <10 mL/min

• Herpes zoster: 500 mg every 24 hours 1
• Genital herpes suppression: 500 mg every 24 hours 1
• Cold sores: 500 mg every 24 hours 1

Hemodialysis

• Administer recommended dose after hemodialysis 1
• Approximately one-third of acyclovir is removed during a 4-hour session 1

Critical Considerations

Caution in immunocompromised patients: Higher doses (8000 mg/day) for prolonged periods have been associated with thrombotic microangiopathy (TMA)-like syndrome, particularly in patients with advanced HIV disease 3. Close monitoring is essential when using high-dose valacyclovir in immunocompromised patients 3.

Renal function monitoring: Valacyclovir should be used with caution in patients with impaired renal clearance 6. Dose adjustment is mandatory based on creatinine clearance 1.

Timing is critical: For all indications, early initiation of therapy (within 48-72 hours of symptom onset) maximizes clinical benefit 1, 4, 5.