Preventative Genital Herpes Medication
For immunocompetent patients with recurrent genital herpes, valacyclovir 500 mg once daily is the recommended first-line suppressive therapy for those with fewer than 10 recurrences per year, while valacyclovir 1000 mg once daily should be used for patients with 10 or more recurrences annually. 1, 2
Primary Suppressive Therapy Regimens
Valacyclovir (Preferred Agent)
- Valacyclovir 500 mg once daily for patients with <10 recurrences per year 1, 2
- Valacyclovir 1000 mg once daily for patients with ≥10 recurrences per year 1, 2
- Reduces recurrence frequency by ≥75% in patients with frequent outbreaks 2
- Documented safety for up to 1 year of continuous use 1, 2
- Superior convenience with once-daily dosing compared to acyclovir 2
Alternative Suppressive Options
- Acyclovir 400 mg twice daily - documented safety for up to 6 years of continuous use 2, 3
- Famciclovir 250 mg twice daily - effective alternative with comparable efficacy 2, 4
Special Population Considerations
HIV-Infected Patients
- Valacyclovir 500 mg twice daily (NOT once daily) is required for adequate suppression in HIV-infected individuals with CD4+ count ≥100 cells/mm³ 1, 2
- Higher dosing is necessary due to potentially more severe and frequent recurrences in immunocompromised patients 1
- Critical pitfall to avoid: Do not prescribe valacyclovir 500 mg once daily for HIV-infected patients—they require twice-daily dosing 2
Renal Impairment
- For CrCl 30-49 mL/min: no dose reduction needed for standard suppressive regimens 1
- For CrCl <30 mL/min: dose adjustments are required to prevent acute renal failure 4, 3
- Patients with substantial renal impairment require monitoring 2
Clinical Management Algorithm
Candidacy Assessment
- Primary candidates: patients with ≥6 recurrences per year 2
- Suppressive therapy should be discussed with every HSV-2-infected patient 1
Duration and Reassessment
- After 1 year of continuous suppressive therapy, discuss discontinuation to reassess recurrence frequency 1, 2
- Recurrences may decrease over time, making continued suppression unnecessary 1
- Safety documented for up to 6 years with acyclovir and 1 year with valacyclovir 1, 2
Monitoring Requirements
- No laboratory monitoring is needed for patients on suppressive therapy unless they have substantial renal impairment 1, 2
Critical Safety Considerations
Thrombotic Thrombocytopenic Purpura/Hemolytic Uremic Syndrome (TTP/HUS)
- High-dose valacyclovir (8 g/day) has been associated with TTP/HUS in immunocompromised patients 1, 5
- This has NOT been reported at doses used for HSV suppression (500-1000 mg/day) 1, 2
- Avoid valacyclovir 8 g/day in immunocompromised patients 5
Common Adverse Effects
- Headache and nausea are the most common side effects, occurring in >10% of patients 4
- Generally mild and well-tolerated 2
Treatment Failure and Resistance
Recognition
- Suspect acyclovir resistance if lesions do not begin to resolve within 7-10 days of appropriate therapy 2, 5
- All acyclovir-resistant strains are also resistant to valacyclovir 1
Management of Resistance
- Obtain viral culture and susceptibility testing if resistance is suspected 2
- IV foscarnet 40 mg/kg every 8 hours is the treatment of choice for acyclovir-resistant HSV 1, 2, 5
Key Counseling Points
Transmission Risk
- Suppressive therapy reduces but does not eliminate asymptomatic viral shedding 1, 2
- Patients can still transmit HSV to partners even while on suppressive therapy 2, 5
- Condom use during all sexual exposures with new or uninfected partners is essential 5
Medication Limitations
- Antiviral medications control symptoms but do not eradicate the virus 5
- Genital herpes remains a recurrent, incurable viral disease 5
Pregnancy Considerations
- The safety of valacyclovir in pregnancy has not been fully established 1, 5
- Current registry findings do not indicate increased risk for major birth defects with acyclovir compared to the general population 1
- Routine suppressive therapy is not recommended during pregnancy for recurrent genital herpes 5