What is the recommended dose of Valtrex (valacyclovir) for treating Herpes Simplex Virus 1 (HSV1)?

Valacyclovir (Valtrex) Dosing for HSV-1 Infections

For HSV-1 cold sores (herpes labialis), the recommended dose of Valtrex is 2 grams twice daily for 1 day, taken 12 hours apart, initiated at the earliest symptom of a cold sore. 1

Dosing Recommendations by HSV-1 Manifestation

Cold Sores (Herpes Labialis)

• Adults and children ≥12 years: 2 grams twice daily for 1 day (12 hours apart) 1
• Therapy should be initiated at the earliest symptom (tingling, itching, or burning)
• Treatment is most effective when started during the prodromal phase or within 1 day of lesion onset 2

Genital HSV-1 Infections

1. Initial Episode:

   • 1 gram twice daily for 10 days 1
   • Most effective when started within 48 hours of symptom onset

2. Recurrent Episodes:

   • 500 mg twice daily for 3 days 1
   • A 3-day course is equivalent in efficacy to a 5-day course 3

3. Suppressive Therapy:

   • Normal immune function: 1 gram once daily 1
   • With ≤9 recurrences per year: 500 mg once daily 1
   • HIV-infected patients (CD4+ ≥100 cells/mm³): 500 mg twice daily 1

4. Reduction of Transmission:

   • 500 mg once daily (for patients with ≤9 recurrences per year) 1

Special Considerations

Renal Dose Adjustments

Creatinine Clearance (mL/min)	Genital Herpes Recurrent	Genital Herpes Suppressive
≥50 (normal)	500 mg every 12 hours	1 gram every 24 hours
30-49	No reduction	No reduction
10-29	500 mg every 24 hours	500 mg every 24 hours
<10	500 mg every 24 hours	500 mg every 24 hours
[2]

Administration

• Valtrex may be given without regard to meals 1
• For patients unable to swallow tablets, an oral suspension can be prepared from 500 mg tablets 1

Efficacy Considerations

• For cold sores, valacyclovir therapy can abort lesion development in approximately 42-47% of cases when initiated during the prodrome/macule stages or within 6 hours of first symptoms 4
• For recurrent genital herpes, valacyclovir 1000 mg once daily is equivalent in efficacy to 500 mg twice daily 5
• Valacyclovir has improved bioavailability compared to acyclovir, allowing for less frequent dosing 6

Common Pitfalls and Caveats

• Timing is critical: Treatment efficacy depends significantly on early initiation at the first sign of symptoms
• Patient education: Instruct patients to:
  • Start medication at the first sign of prodrome
  • Wash hands before and after application
  • Complete the full prescribed course even if symptoms improve 2
• Transmission risk: Patients should be counseled that:
  • They should abstain from sexual activity when lesions or prodromal symptoms are present
  • Asymptomatic viral shedding can still lead to transmission
  • Consistent condom use reduces transmission risk 2

Immunocompromised Patients

• Higher doses and longer treatment durations may be necessary
• For HIV-infected patients with CD4+ count ≥100 cells/mm³, use 500 mg twice daily for suppressive therapy 2, 1
• Close monitoring is required to prevent adverse effects