What is the recommended treatment for acute Herpes Simplex Virus (HSV) one infection?

Treatment for Acute HSV-1 Infection

For acute HSV-1 infection, treat with oral acyclovir 400 mg three times daily for 5 days, initiated during prodrome or within 2 days of lesion onset for maximum benefit. 1, 2

First Clinical Episode (Primary Infection)

For patients presenting with their first HSV-1 outbreak, the treatment approach differs based on severity:

Mild to Moderate Disease

• Acyclovir 200 mg orally 5 times daily for 7-10 days until clinical resolution is the CDC-recommended regimen for first clinical episodes 3, 1
• This longer duration (compared to recurrent episodes) is necessary because primary infections typically present with more extensive disease and prolonged viral shedding 3

Severe Disease Requiring Hospitalization

• Acyclovir 5-10 mg/kg IV every 8 hours for 5-7 days or until clinical resolution for patients with extensive disease 1, 4
• The FDA label supports IV acyclovir for initial and recurrent mucosal and cutaneous HSV in immunocompromised patients and severe initial episodes in immunocompetent patients 4

Recurrent Episodes (Orolabial Herpes/Cold Sores)

The CDC provides three equally effective oral regimens, all for 5 days duration 1, 2:

• Acyclovir 400 mg orally 3 times daily (most convenient option) 1, 2
• Acyclovir 800 mg orally twice daily 1, 2
• Acyclovir 200 mg orally 5 times daily 1, 2

Critical Timing Consideration

• Treatment must be initiated during prodrome or within 2 days of lesion onset for any meaningful clinical benefit 1, 2
• Starting therapy after this window significantly reduces effectiveness, and most immunocompetent patients with recurrent disease experience limited benefit from delayed therapy 2
• The 800 mg twice-daily regimen demonstrates shorter symptom duration (8.1 vs 12.5 days with placebo) and reduced pain duration (2.5 vs 3.9 days with placebo) when initiated early 2

Chronic Suppressive Therapy

For patients with frequent recurrences (≥6 episodes per year):

• Acyclovir 400 mg orally twice daily reduces recurrence frequency by at least 75% 3, 1
• Alternative regimen: Acyclovir 200 mg orally 3-5 times daily, with the goal of identifying the lowest effective dose 3, 1
• Safety and efficacy documented for up to 5 years of continuous use 3
• Discontinue after 1 year to reassess recurrence rate 3

Special Populations

Immunocompromised Patients

• May require more aggressive therapy with prolonged treatment courses beyond standard recommendations 3, 1
• Immunocompromised hosts may develop severe disease refractory to standard antiviral therapy 5
• If lesions fail to resolve within 7-10 days, suspect acyclovir resistance and consider foscarnet 40 mg/kg IV every 8 hours 6, 5

HIV-Infected Patients

• Require closer monitoring and may need longer treatment courses than recommended for immunocompetent patients 3
• Healing may be slower and treatment failures occur more frequently, especially with shorter-course regimens 3

Common Pitfalls to Avoid

Topical Acyclovir

• Do not use topical acyclovir as primary therapy - it is substantially less effective than oral formulations and provides no improvement in systemic symptoms 3, 1, 6, 7

Patient Counseling

• Patients must understand that acyclovir neither eradicates latent virus nor affects subsequent risk, frequency, or severity of recurrences after discontinuation 3, 2
• Advise abstaining from activities that might spread the virus while lesions are present 2
• Transmission can occur during asymptomatic periods through viral shedding 6

Dosing Adjustments

• Geriatric patients and those with renal impairment require dose reduction due to higher acyclovir plasma concentrations 4
• Acyclovir-resistant strains have been isolated from patients on suppressive therapy but are not typically associated with treatment failure in immunocompetent patients 3