Valtrex Dosing for Cold Sores
For cold sores (herpes labialis), the recommended dose of Valtrex is 2 grams twice daily for 1 day, with the two doses taken 12 hours apart, initiated at the earliest symptom such as tingling, itching, or burning. 1
Treatment Regimen Details
- The FDA-approved dosing is specifically 2 grams taken twice in a single day (total of 4 grams over 24 hours), not extended beyond this 1-day period 1
- Treatment must be initiated at the very first prodromal symptoms (tingling, itching, burning) before visible lesions develop for maximum effectiveness 1
- The two doses should be spaced approximately 12 hours apart 1
- Valtrex may be taken without regard to meals 1
Evidence Supporting This Regimen
- Two large randomized, placebo-controlled trials demonstrated that this 1-day, high-dose regimen reduced the median duration of cold sore episodes by 1.0 day compared to placebo (P = 0.001) 2
- The 1-day regimen prevented or blocked lesion development in an additional 6-8% of patients compared to placebo 2
- Time to lesion healing and time to cessation of pain were both statistically significantly reduced with this valacyclovir regimen 2
- This short-course, high-dose approach is supported by guideline recommendations recognizing that oral valacyclovir accelerates healing and decreases pain in recurrent herpes labialis 3
Critical Timing Considerations
- There are no data on effectiveness of treatment initiated after visible cold sore lesions have already developed (papule, vesicle, or ulcer stage) 1
- Patient-initiated therapy at the earliest prodromal symptoms may even prevent lesion development entirely 3
- Patients should be provided with medication in advance so they can initiate treatment immediately when symptoms begin 1
Safety Profile
- This regimen is generally well tolerated with minimal adverse events 3
- Headache is the most common side effect, occurring slightly more frequently than placebo 3
- Other mild adverse events include nausea, diarrhea, dyspepsia, dry mouth, and flatulence, but these occur at similar rates to placebo 3
- Patients should maintain adequate hydration during treatment 1
Important Counseling Points
- Valtrex is not a cure for cold sores 1
- Treatment should not exceed 1 day (2 doses total) for cold sores 1
- If a dose is missed, take it as soon as remembered, but do not double the next dose 1
- Resistance to valacyclovir remains extremely rare (<0.5%) in immunocompetent patients despite over 20 years of widespread use 3