What is the recommended treatment and dosage of Valcyclovir (valacyclovir) for herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections?

Valacyclovir Treatment Recommendations for HSV and VZV Infections

Valacyclovir is the recommended first-line oral treatment for herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections due to its superior bioavailability compared to acyclovir, allowing for less frequent dosing while maintaining efficacy. 1, 2

Herpes Simplex Virus (HSV) Treatment

Genital Herpes

• First episode:

  • 1 gram twice daily for 7-10 days 1
  • Initiate at earliest symptoms for maximum effectiveness

• Recurrent episodes:

  • 500 mg twice daily for 3-5 days 1
  • Initiate within 24 hours of symptom onset

• Suppressive therapy:

  • Immunocompetent patients: 1 gram once daily 1
  • For patients with ≤9 recurrences per year: 500 mg once daily 1
  • HIV-infected patients: 500 mg twice daily 1

Cold Sores (Herpes Labialis)

• Adults and children ≥12 years:
  • 2 grams twice daily for 1 day (doses taken 12 hours apart) 1
  • Initiate at earliest symptom (tingling, itching, or burning)

Varicella-Zoster Virus (VZV) Treatment

Herpes Zoster (Shingles)

• Adults:
  • 1 gram three times daily for 7 days 1, 3
  • Alternative dosing: 1.5 grams twice daily for 7 days 3
  • Initiate within 72 hours of rash onset for maximum effectiveness 4

Chickenpox

• Children 2 to <18 years:
  • 20 mg/kg three times daily for 5 days (not to exceed 1 gram three times daily) 1
  • Initiate at earliest sign or symptom

Prophylaxis Recommendations

HSV Prophylaxis

• Recommended for all patients with recurrent HSV infections undergoing immunosuppressive therapy 5
• Continue until immunosuppression resolves or as directed by specific clinical scenario 5

VZV Prophylaxis

• Recommended for at least 1 year after allogeneic hematopoietic cell transplantation in VZV-seropositive patients 5
• Consider for 6-12 months in autologous transplant recipients 5
• Consider for patients receiving T-cell depleting agents or bortezomib 5

Dosage Adjustments for Renal Impairment

Creatinine Clearance (mL/min)	Cold Sores	Genital Herpes (Recurrent)	Genital Herpes (Suppressive)	Herpes Zoster
30-49	No reduction	No reduction	No reduction	1g every 12h
10-29	500mg every 24h	500mg every 24h	500mg every 24h	1g every 24h
<10	500mg every 24h	500mg every 24h	500mg every 24h	500mg every 24h

1

Special Populations

Immunocompromised Patients

• Higher doses and longer treatment durations may be required 5, 4
• For HSV prophylaxis in stem cell transplant recipients: acyclovir or valacyclovir until day 30 post-transplant 5
• For VZV prophylaxis in high-risk patients: consider long-term prophylaxis 5

Pediatric Patients

• Cold sores: Approved for children ≥12 years 1
• Chickenpox: Approved for children 2 to <18 years 1
• Not recommended for children <2 years with chickenpox due to insufficient data 1

Clinical Pearls and Pitfalls

• Valacyclovir provides 3-5 times greater bioavailability of acyclovir compared to oral acyclovir itself 2
• Initiate treatment within 72 hours of rash onset for herpes zoster to maximize effectiveness 4
• For recurrent genital herpes, treatment should begin at the earliest sign of recurrence 1
• Monitor renal function and adjust dosage accordingly, especially in elderly patients 1
• Thrombotic microangiopathy has been reported with high-dose valacyclovir (8g/day) in severely immunocompromised patients 6
• Valacyclovir is not recommended for treatment of herpes zoster in children due to limited safety data 1

Valacyclovir's convenient dosing regimen (1-3 times daily versus 5 times daily for acyclovir) improves patient compliance while maintaining efficacy, making it a preferred choice for both treatment and prophylaxis of HSV and VZV infections 2, 3.