What is the recommended dosing of Valtrex (valacyclovir) for treating HSV-1 (Herpes Simplex Virus 1) cold sores?

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Last updated: June 23, 2025View editorial policy

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From the Guidelines

For treating HSV-1 cold sores, the recommended dosing of Valtrex (valacyclovir) is 2 grams twice daily for 1 day, with the second dose taken 12 hours after the first dose 1. This dosing regimen is based on the most effective treatment strategy for reducing the severity and duration of cold sore symptoms.

  • The treatment should be initiated at the first sign of symptoms, ideally during the prodromal phase, when the patient experiences tingling, itching, or burning sensations before the appearance of the cold sore.
  • Valtrex works by inhibiting viral DNA replication, thereby preventing the virus from multiplying and reducing the duration of the outbreak.
  • Potential side effects of Valtrex include headache, nausea, and dizziness, and patients with kidney problems may require a lower dose.
  • For patients experiencing frequent outbreaks (more than 6 per year), daily suppressive therapy with 500-1000 mg once daily may be prescribed to reduce recurrence.
  • It is essential to complete the prescribed regimen, even if symptoms improve before finishing the medication, to ensure optimal treatment outcomes.
  • The dosing recommendations are based on guidelines from reputable sources, including the Centers for Disease Control and Prevention 1.

From the FDA Drug Label

The recommended dosage of VALTREX for treatment of cold sores is 2 grams twice daily for 1 day taken 12 hours apart. Therapy should be initiated at the earliest symptom of a cold sore (e.g., tingling, itching, or burning). The recommended dosage of VALTREX for the treatment of cold sores in pediatric patients aged greater than or equal to 12 years is 2 grams twice daily for 1 day taken 12 hours apart. Therapy should be initiated at the earliest symptom of a cold sore (e.g., tingling, itching, or burning).

The recommended dosing of Valtrex (valacyclovir) for treating HSV-1 (Herpes Simplex Virus 1) cold sores is:

  • 2 grams twice daily for 1 day, taken 12 hours apart, for adults and pediatric patients aged greater than or equal to 12 years.
  • Therapy should be initiated at the earliest symptom of a cold sore, such as tingling, itching, or burning. 2 2

From the Research

Valtrex Dosing for HSV-1 Cold Sores

The recommended dosing of Valtrex (valacyclovir) for treating HSV-1 (Herpes Simplex Virus 1) cold sores is as follows:

  • 2 g of valacyclovir twice daily for 1 day, which has been shown to reduce the median duration of the episode by 1.0 day compared to placebo 3
  • Alternatively, a 2-day treatment regimen of 2 g of valacyclovir twice daily for 1 day, followed by 1 g of valacyclovir twice daily for 1 day, can also be effective in reducing the duration of the episode 3

Key Findings

  • High-dose, short-duration valacyclovir therapy has been found to be safe and effective in the treatment of cold sores 3
  • The 1-day valacyclovir regimen offers patients a unique and convenient dosing alternative compared to available topical therapies 3
  • Valacyclovir is well tolerated at dosages used to suppress recurrent episodes of genital herpes (500 to 1000 mg/day) in immunocompetent and HIV seropositive individuals 4

Comparison with Other Treatments

  • Penciclovir cream has been shown to be a effective topical treatment for herpes simplex infections, with a significant decrease in time to lesion healing, lesion area, and pain compared to acyclovir cream 5
  • Valacyclovir has been found to be effective in the treatment of uncomplicated herpes zoster in immunocompetent patients, with a twice-daily dosing regimen being as safe and effective as a three-times-daily regimen 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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