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

Valtrex (Valacyclovir) Dosing for Cold Sores

The recommended dosage of Valtrex (valacyclovir) for treatment of cold sores is 2 grams twice daily for 1 day taken 12 hours apart. 1

Dosing Regimen

• Therapy should be initiated at the earliest symptom of a cold sore (e.g., tingling, itching, or burning) for maximum effectiveness 1
• The 1-day treatment regimen (2g twice daily) is preferred over longer treatment courses as it provides similar efficacy with greater convenience 2
• The medication may be taken without regard to meals 1

Clinical Evidence

• High-dose, short-duration valacyclovir therapy has been shown to significantly reduce:
  • The median duration of cold sore episodes by approximately 1 day compared to placebo 2
  • The time to lesion healing 2
  • The time to cessation of pain and discomfort 2
• This 1-day regimen offers a convenient dosing alternative compared to available topical therapies 2
• Valacyclovir has better oral bioavailability than acyclovir, increasing acyclovir bioavailability three- to fivefold 2

Safety Considerations

• Valacyclovir is generally well-tolerated with minimal adverse events in patients 3
• Common side effects may include:
  • Headache (more common with valacyclovir than with placebo) 3
  • Nausea and diarrhea (similar rates to placebo) 3
  • Less commonly: dyspepsia, dry mouth, and flatulence 3
• No serious adverse events have been reported in clinical trials for cold sore treatment 3

Special Populations

• For pediatric patients aged 12 years and older, the dosage is the same as adults: 2 grams twice daily for 1 day taken 12 hours apart 1
• Patients with significant renal impairment may require dose adjustment 4

Treatment Timing

• Early initiation of therapy is crucial for maximum effectiveness 3
• Patient-initiated episodic therapy at the first symptoms may even prevent lesion development in some cases 3
• Starting treatment during the prodromal phase (before visible lesions appear) provides the best outcomes 1, 2

Potential Pitfalls

• Delayed initiation of therapy significantly reduces effectiveness - patients should be instructed to start treatment at the earliest symptoms 3
• Resistance to valacyclovir remains low (<0.5% in immunocompetent hosts) and is not a major concern for episodic treatment of cold sores 3
• Patients should complete the full course of therapy (both doses) even if symptoms begin to improve 1

This high-dose, short-duration regimen provides a simple and effective treatment option that maximizes convenience while maintaining efficacy for managing cold sores.