What is the prophylactic dose of Valacyclovir (valacyclovir) for recurrent genital herpes?

Prophylactic Dosing of Valacyclovir for Recurrent Genital Herpes

For prophylactic treatment of recurrent genital herpes, valacyclovir should be dosed at 500 mg once daily for patients with fewer than 10 recurrences per year, or 1000 mg once daily for patients with 10 or more recurrences per year. 1, 2, 3

Dosing Recommendations Based on Recurrence Frequency

For patients with <10 recurrences per year:

• Valacyclovir 500 mg orally once daily 1, 2

For patients with ≥10 recurrences per year:

• Valacyclovir 1000 mg orally once daily 1, 3
• Alternative: Valacyclovir 500 mg orally twice daily 2

Efficacy and Evidence

Daily suppressive therapy with valacyclovir has been shown to reduce the frequency of genital herpes recurrences by ≥75% among patients with frequent recurrences 2. Clinical trials have demonstrated that valacyclovir prevents or delays approximately 85% of recurrences that would have occurred with placebo 4.

The FDA-approved drug label specifically indicates that for chronic suppressive therapy of recurrent genital herpes 1:

• 1 gram once daily is recommended for patients with normal immune function
• 500 mg once daily is an alternative for patients with 9 or fewer recurrences per year
• For reduction of transmission, 500 mg once daily is recommended for the source partner with ≤9 recurrences per year

Special Populations

HIV-infected patients:

• Valacyclovir 500 mg twice daily is recommended for chronic suppressive therapy of recurrent genital herpes in HIV-1-infected patients with CD4+ cell count ≥100 cells/mm³ 1, 2

Duration of Therapy

Safety and efficacy have been documented for up to 1 year with valacyclovir 2. After 1 year of continuous suppressive therapy, discontinuation should be discussed with the patient to assess psychological adjustment to genital herpes and rate of recurrent episodes, as the frequency of recurrences often decreases over time 2.

Important Clinical Considerations

• Suppressive treatment reduces but does not eliminate asymptomatic viral shedding 2
• Valacyclovir has better oral bioavailability than acyclovir, allowing for less frequent dosing 5
• Patients should still be counseled to:
  • Abstain from sexual activity when lesions or prodromal symptoms are present
  • Use condoms during all sexual exposures with new or uninfected partners
  • Inform sex partners about their genital herpes status 2

Monitoring and Adverse Events

Valacyclovir is generally well-tolerated at dosages used for suppression of recurrent genital herpes (500-1000 mg/day) 5. No laboratory monitoring is needed unless the patient has substantial renal impairment 2. The most common adverse effects include headache and gastrointestinal complaints 5.

Pitfalls to Avoid

• Do not use short-course therapy (1-3 days) for patients with HIV infection 2
• Valacyclovir 500 mg once daily appears less effective for patients with very frequent recurrences (≥10 episodes per year) 2
• Dose adjustment is necessary in patients with renal impairment 6
• High-dose valacyclovir (8 g/day) has been associated with thrombotic microangiopathy in immunocompromised patients, but this is not a concern at the standard prophylactic doses for genital herpes 5