What is the recommended dose of Valtrex (valacyclovir) for a 50-year-old male with simplex dermatitis presumed to be related to herpes simplex virus infection?

Valacyclovir Dosing for Herpes Simplex Dermatitis in a 50-Year-Old Male

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

FDA-Approved Dosing for Cold Sores

• The FDA label explicitly states that for cold sores (herpes labialis), valacyclovir should be dosed as 2 grams twice daily for 1 day, with doses separated by 12 hours 1
• Therapy must be initiated at the earliest symptom of a cold sore (prodromal phase: tingling, itching, or burning) for maximum efficacy 1
• This single-day, high-dose regimen is the only FDA-approved dosing for herpes labialis in adults 1

Clinical Efficacy Evidence

• Short-course valacyclovir (2 grams twice daily for 1 day) significantly reduces median episode duration to approximately 5.0 days compared to 6.2 days with placebo 2
• The single-day regimen demonstrated a shorter time to return to normal skin (2.9 days vs 4.5 days with placebo, p < 0.001) 2
• Early initiation during the prodromal phase is critical—delaying treatment beyond the first 24 hours substantially reduces efficacy 2

Important Distinctions: This is NOT Genital Herpes

• Do not confuse herpes labialis dosing with genital herpes dosing—the conditions require different regimens despite being caused by HSV 1
• For genital herpes recurrent episodes, the dose would be 500 mg twice daily for 3-5 days, which is inappropriate for cold sores 3, 1
• For genital herpes suppressive therapy, the dose would be 500-1000 mg once daily, which is not indicated for episodic cold sore treatment 3, 4, 1

Administration and Practical Considerations

• Valacyclovir may be given without regard to meals 1
• No dose adjustment is needed for patients with creatinine clearance ≥30 mL/min 3
• The medication should be readily accessible to the patient so they can self-initiate at the first prodromal symptom—any delay reduces effectiveness 2

Common Pitfalls to Avoid

• Do not prescribe 500 mg twice daily for 5 days (the genital herpes recurrent episode dose) for cold sores—this is off-label and not supported by FDA approval 1
• Do not prescribe daily suppressive therapy (500-1000 mg once daily) for episodic cold sores unless the patient has frequent recurrences (≥6 per year) and specifically requests suppression rather than episodic treatment 3, 5
• Do not delay treatment—emphasize to the patient that they must start therapy immediately when they feel the first tingling or prodromal symptoms 2, 1

When to Consider Suppressive Therapy Instead

• If this 50-year-old male experiences ≥6 cold sore recurrences per year, discuss daily suppressive therapy with valacyclovir 500 mg once daily 3
• Suppressive therapy reduces recurrence frequency by ≥75% in patients with frequent outbreaks 3, 4
• However, for a single episode or infrequent recurrences, the episodic 2-gram twice-daily regimen remains the standard of care 1