Valacyclovir Dosing for HSV-1 Infections
For HSV-1 oral herpes (cold sores), the recommended dose is valacyclovir 2 grams twice daily for 1 day, taken 12 hours apart, initiated at the earliest symptom. 1
Treatment Regimens by Clinical Presentation
Orolabial HSV-1 (Cold Sores)
- The FDA-approved regimen is valacyclovir 2 grams twice daily for 1 day (total of 2 doses, 12 hours apart) 1
- Therapy must be initiated at the earliest symptom such as tingling, itching, or burning for maximum efficacy 1
- This single-day regimen provides superior convenience while maintaining equivalent efficacy to longer courses 2
- Treatment initiated during prodrome or within 2 days of lesion onset provides maximum benefit 2
Genital HSV-1 (if applicable)
Initial Episode:
- Valacyclovir 1 gram twice daily for 10 days 1
- Most effective when administered within 48 hours of symptom onset 1
Recurrent Episodes:
- Valacyclovir 500 mg twice daily for 3 days 1
- Initiate at the first sign or symptom of an episode 1
- The CDC recommends valacyclovir 500 mg twice daily for 5 days as an alternative regimen for HSV recurrent episodes 3
Suppressive Therapy:
- Valacyclovir 1000 mg once daily for patients with normal immune function 1
- Alternative dose of 500 mg once daily for patients with 9 or fewer recurrences per year 1
- Reduces recurrence frequency by ≥75% 3
Critical Timing Considerations
- Treatment effectiveness is highly time-dependent - therapy initiated within 48 hours of symptom onset provides optimal results 3
- For recurrent HSV, treatment at prodrome provides maximum benefit 3
- Starting therapy after the 48-hour window significantly reduces effectiveness 2
- Patients should be provided with medication in advance to enable immediate self-initiated treatment 3
Important Clinical Caveats
- Valacyclovir does not eradicate latent virus and does not affect subsequent risk, frequency, or severity of recurrences after discontinuation 2
- Suppressive therapy reduces but does not eliminate asymptomatic viral shedding, and transmission can occur even during asymptomatic periods 3
- Most immunocompetent patients with recurrent disease experience limited benefit from delayed therapy 2
- Patients should abstain from activities that might spread the virus while lesions are present 2
Special Populations and Severe Disease
Immunocompromised Patients:
- For HIV-infected patients with CD4+ count ≥100 cells/mm³, use valacyclovir 500 mg twice daily for suppressive therapy 1
- Avoid valacyclovir doses of 8 grams per day in immunocompromised patients due to risk of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome 3
Severe Disease Requiring Hospitalization:
- For severe HSV infection with complications (disseminated infection, pneumonitis, hepatitis, or CNS involvement), use IV acyclovir 5-10 mg/kg every 8 hours for 5-7 days or until clinical resolution instead of oral valacyclovir 3
Renal Impairment:
- Dosage adjustment is necessary for patients with reduced renal function 4