What is the recommended dose of Valtrex (valacyclovir) for the treatment of Herpes Simplex Virus 1 (HSV-1) infections?

Valacyclovir Dosing for HSV-1 Infections

For HSV-1 infections, valacyclovir (Valtrex) should be dosed at 1 gram twice daily for 7-10 days for first episodes and 500 mg twice daily for 5 days for recurrent episodes. 1

First Episode HSV-1 Treatment

For patients experiencing their first clinical episode of HSV-1 infection:

• Recommended regimen: Valacyclovir 1 gram orally twice daily for 7-10 days 2, 1
• Treatment may be extended if healing is incomplete after 10 days of therapy
• Therapy is most effective when initiated within 48 hours of symptom onset

Recurrent HSV-1 Episodes

For patients with recurrent HSV-1 infections:

• Recommended regimen: Valacyclovir 500 mg orally twice daily for 5 days 2, 1
• Treatment should begin at the earliest sign of recurrence (prodrome or lesions)
• For cold sores specifically (herpes labialis): Valacyclovir 2 grams twice daily for 1 day taken 12 hours apart 1

Suppressive Therapy for Frequent Recurrences

For patients with frequent HSV-1 recurrences (≥6 episodes per year):

• Recommended regimen:
  • Valacyclovir 500 mg orally once daily 2, 1
  • For patients with very frequent recurrences (≥10 episodes per year): Valacyclovir 1 gram once daily 1

Special Populations

Immunocompromised Patients (including HIV)

• Recommended regimen: Valacyclovir 500 mg twice daily for suppressive therapy 2
• For severe cases in immunocompromised patients: Consider IV acyclovir 5-10 mg/kg every 8 hours 2
• Short-course therapy (1-3 days) should NOT be used in HIV-infected patients 2

Pediatric Patients

• For children ≥12 years with cold sores: Valacyclovir 2 grams twice daily for 1 day 1
• For children <12 years: Acyclovir is typically used instead of valacyclovir 2

Important Clinical Considerations

• Valacyclovir has better oral bioavailability than acyclovir, allowing for less frequent dosing 3
• Valacyclovir not only treats symptoms but also reduces viral shedding, which may decrease transmission risk 4
• Treatment efficacy decreases if initiated more than 48 hours after symptom onset
• Common side effects include headache and nausea, but these are generally mild 3

Pitfalls to Avoid

• Do not use high-dose valacyclovir (8 g/day) in immunocompromised patients due to risk of thrombotic microangiopathy 3
• Do not delay treatment - efficacy is highest when started at the earliest signs of infection
• Do not use topical acyclovir as it is substantially less effective than oral therapy 2
• Do not use short-course therapy in immunocompromised patients 2
• Renal dose adjustment is necessary for patients with impaired kidney function 1

Valacyclovir is well-tolerated and provides the convenience of less frequent dosing compared to acyclovir, which may improve treatment adherence 5.