Valacyclovir Dosing for Cold Sores
The recommended dosage of valacyclovir for treatment of cold sores (herpes labialis) is 2 grams twice daily for 1 day, with doses taken 12 hours apart. 1 This high-dose, short-duration regimen should be initiated at the earliest symptom of a cold sore, such as tingling, itching, or burning.
Evidence-Based Rationale
The FDA-approved dosing recommendation is supported by high-quality clinical evidence demonstrating that this regimen effectively reduces:
- Duration of cold sore episodes by approximately 1 day compared to placebo 2
- Time to lesion healing 2
- Time to cessation of pain and discomfort 2
The 1-day treatment regimen (2g twice daily) has been shown to be more effective than a 2-day regimen (2g twice daily for day 1, then 1g twice daily for day 2) in reducing the median duration of cold sore episodes 2, 3.
Treatment Algorithm
Initiation timing: Begin treatment at the earliest symptom (prodrome) of a cold sore
- Early signs include tingling, itching, or burning sensation
- Efficacy is maximized when treatment starts during the prodromal phase
Dosing schedule:
- First dose: 2 grams of valacyclovir
- Second dose: 2 grams of valacyclovir 12 hours after the first dose
- Complete the full treatment (both doses) even if symptoms improve
Administration: May be taken with or without food 1
Special Considerations
Renal Impairment
Dosage adjustments are required for patients with reduced renal function 1:
- Creatinine clearance 30-49 mL/min: No reduction needed
- Creatinine clearance 10-29 mL/min: 1 gram every 24 hours (do not exceed 1 day)
- Creatinine clearance <10 mL/min: 500 mg every 24 hours (do not exceed 1 day)
Hemodialysis
Patients requiring hemodialysis should receive the recommended dose after hemodialysis 1.
Clinical Pearls
- The 1-day valacyclovir regimen offers patients a convenient dosing alternative compared to topical therapies 2
- Valacyclovir is better absorbed than oral acyclovir, increasing acyclovir bioavailability three- to fivefold 2
- Treatment is most effective when initiated during the prodromal phase, before visible lesions appear
- Patients should be advised that early treatment can prevent lesion development in some cases or reduce the severity and duration of the episode 3
- This high-dose, short-duration regimen has a safety profile similar to placebo in clinical trials 2
Patient Education
- Store medication at room temperature
- Complete the full course of treatment (both doses)
- Treatment should be initiated at the earliest symptom of a cold sore for maximum effectiveness
- Patients may self-medicate as soon as they feel the prodrome of a herpes labialis outbreak 4
- Advise patients to abstain from close contact with others during active lesions to prevent transmission