What is the typical dosing regimen for valacyclovir (Valtrex) in the treatment of genital herpes and herpes zoster (shingles)?

Valacyclovir Dosing for Genital Herpes and Herpes Zoster

For genital herpes, valacyclovir is dosed at 1 gram twice daily for 10 days for initial episodes, 500 mg twice daily for 3 days for recurrent episodes, and 500-1000 mg once daily for suppressive therapy, while herpes zoster requires 1 gram three times daily for 7 days. 1, 2

Genital Herpes Treatment

Initial Episode

• Valacyclovir 1 gram orally twice daily for 10 days 2
• Therapy is most effective when initiated within 48 hours of symptom onset
• Alternative: Acyclovir 400 mg orally three times daily for 7-10 days 1

Recurrent Episodes

• Valacyclovir 500 mg orally twice daily for 3 days 1, 2
• Start treatment at the first sign or symptom of an episode (prodrome)
• Patient should be provided with medication or prescription to initiate treatment promptly
• Alternative: Acyclovir 800 mg orally twice daily for 5 days 1

Suppressive Therapy

• For patients with normal immune function:

  • Valacyclovir 1 gram orally once daily 1, 2
  • For patients with ≤9 recurrences per year: 500 mg orally once daily 1, 2
  • Note: 500 mg once daily appears less effective for patients with ≥10 recurrences per year 1

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

  • Valacyclovir 500 mg orally twice daily 2
  • Higher doses may be needed for immunocompromised patients 1

Herpes Zoster (Shingles) Treatment

• Valacyclovir 1 gram orally three times daily for 7 days 2
• Initiate at earliest sign or symptom of herpes zoster
• Most effective when started within 48 hours of rash onset
• For severe disease requiring hospitalization: Acyclovir 5-10 mg/kg IV every 8 hours for 5-7 days 1

Special Considerations

Immunocompromised Patients

• HIV-infected patients may require higher doses and longer duration of therapy 1
• Close monitoring is required in immunocompromised patients receiving high-dose valacyclovir
• Caution: High-dose valacyclovir (8 g/day) has been associated with thrombotic microangiopathy in severely immunocompromised patients 3

Renal Impairment

• Dosage adjustment required for patients with reduced renal function 2
• Consult product labeling for specific dosing recommendations based on creatinine clearance

Clinical Pearls

• Valacyclovir provides increased bioavailability compared to acyclovir, allowing for less frequent dosing 3, 4
• Patient education should include information about:
  • Abstaining from sexual activity during outbreaks
  • Potential for asymptomatic viral shedding and transmission
  • Importance of informing sexual partners about infection
  • Risk of neonatal infection for childbearing women 1
• Suppressive therapy reduces recurrences by ≥75% among patients with frequent episodes 1
• Valacyclovir may be taken without regard to meals 2
• Allergic and adverse reactions to valacyclovir are infrequent 1

Remember that early treatment initiation (within 48 hours of symptom onset for initial episodes and at first sign of prodrome for recurrences) significantly improves outcomes and may prevent progression of outbreaks.