What is the recommended dose of Valtrex (valacyclovir) for treating cold sores?

Valtrex Dose for Cold Sores

For cold sores (herpes labialis), the recommended dose of Valtrex is 2 grams twice daily for 1 day, with doses taken 12 hours apart, initiated at the earliest symptom (tingling, itching, or burning). 1

Dosing Regimen

• Adults and adolescents ≥12 years: 2 grams orally twice daily for 1 day (total of 2 doses, 12 hours apart) 1
• Pediatric patients <12 years: Valtrex is not approved for cold sore treatment in this age group 1
• The medication may be taken without regard to meals 1

Critical Timing Considerations

Early initiation is essential for maximum effectiveness:

• Treatment must be started at the very first symptoms of a cold sore (prodromal symptoms such as tingling, itching, or burning) 1
• Patient-initiated episodic therapy at first symptoms may even prevent lesion development in some cases 2
• Delayed initiation significantly reduces treatment effectiveness 2
• Patients should be provided with medication in advance so they can begin treatment immediately when symptoms appear 2

Evidence Supporting This Regimen

The 1-day, high-dose valacyclovir regimen has robust clinical trial support:

• This dosing reduced median episode duration by 1.0 day compared to placebo (p=0.001) 3
• Mean episode duration was reduced by 1.1 days with statistical significance 3
• Time to lesion healing and cessation of pain/discomfort were significantly reduced 3
• The proportion of patients in whom lesion development was prevented or blocked increased by 6.4-8.5% compared to placebo 3
• The 1-day regimen proved as effective as a 2-day regimen, supporting the simplified dosing 3

Safety Profile

• Valacyclovir is generally well-tolerated with minimal adverse events 2
• Common side effects include headache (more common than placebo), nausea, and diarrhea 2
• No serious adverse events have been reported in clinical trials for cold sore treatment 2
• Adverse effects were similar across treatment groups in pivotal trials 3
• Resistance remains low (<0.5% in immunocompetent hosts) and is not a concern for episodic treatment 2

Special Populations

Renal impairment: Patients with significant renal impairment may require dose adjustment, though specific cold sore dosing adjustments are not detailed in the FDA label for the 1-day regimen 2, 1

Clinical Advantages

This high-dose, short-duration regimen offers practical benefits over older treatments:

• Simplified dosing: Only 2 doses over 1 day versus topical therapies requiring multiple daily applications 3
• Better compliance: The convenient dosing schedule enhances adherence compared to more frequent regimens 3
• Proven efficacy: Delivers therapeutic acyclovir concentrations due to valacyclovir's superior bioavailability (3-5 fold greater than oral acyclovir) 3