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 for valacyclovir in adults and pediatric patients aged 12 years and older with 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. 1
From the Research
For cold sores, valacyclovir is typically dosed at 2 grams taken twice in one day, with the second dose taken about 12 hours after the first, as this regimen has been shown to be safe and effective in reducing the duration of the episode and the time to lesion healing 2. This short-course therapy should be started at the earliest sign of a cold sore (tingling, itching, or burning sensation). Some key points to consider when prescribing valacyclovir for cold sores include:
- The medication is most effective when started during the prodromal phase before the blister appears
- Common side effects may include headache, nausea, and dizziness
- Patients should maintain adequate hydration while taking valacyclovir and should complete the full prescribed course even if symptoms improve quickly
- For patients with frequent recurrences (more than 6 episodes per year), suppressive therapy with 500 mg once daily may be considered, although the provided evidence does not directly support this dosing regimen for cold sores, it is a common practice for genital herpes 3, 4 It's worth noting that valacyclovir works by converting to acyclovir in the body, which inhibits viral DNA synthesis and replication of herpes simplex virus. The evidence from the studies 2, 3, 5, 4, 6 supports the use of valacyclovir for the treatment of herpes simplex virus infections, including cold sores, and demonstrates its safety and efficacy in both immunocompetent and immunocompromised patients. However, the most recent and highest quality study 2 provides the strongest evidence for the recommended dosing regimen of 2 grams taken twice in one day.