What is the recommended dose of Acyclovir (antiviral medication) for herpes simplex virus prophylaxis?

Acyclovir Prophylaxis Dosing

For HSV suppression, acyclovir 400 mg orally twice daily is the recommended prophylactic dose, which should be continued for up to 12 months followed by re-evaluation of recurrence patterns. 1

Standard Prophylactic Regimens for HSV

The CDC guidelines establish clear dosing options for herpes simplex virus suppression:

• Primary recommendation: Acyclovir 400 mg orally twice daily 1
• Alternative regimen: Acyclovir 200 mg orally 3-5 times daily 1
• After 1 year of continuous suppressive therapy, discontinue acyclovir to reassess the patient's recurrence rate 1

Expected Clinical Outcomes

• Suppressive therapy reduces HSV recurrence frequency by at least 75% in patients with frequent recurrences (≥6 episodes per year) 1
• Suppressive acyclovir reduces but does not eliminate asymptomatic viral shedding 1
• The drug does not eradicate latent virus or affect subsequent risk, frequency, or severity of recurrences after discontinuation 2

Special Population Dosing

HIV-Infected and Immunocompromised Patients

Higher doses are required for immunocompromised patients:

• Acyclovir 400 mg orally 3-5 times daily is often beneficial for HIV-infected patients 3, 1
• Famciclovir 500 mg twice daily has been effective in decreasing recurrence rates and subclinical shedding in HIV-infected patients 1
• For severe cases requiring hospitalization, IV acyclovir 5-10 mg/kg body weight every 8 hours for 5-7 days or until clinical resolution 3, 2

Bortezomib-Treated Patients (Herpes Zoster Prophylaxis)

For patients receiving bortezomib chemotherapy:

• Acyclovir 400 mg once daily during the entire bortezomib treatment period is effective for herpes zoster prophylaxis 4
• Ultra-low-dose acyclovir 200 mg once daily continuously has also demonstrated efficacy in preventing herpes zoster reactivation 5

Critical Pitfalls to Avoid

• Do not use valacyclovir 500 mg once daily in patients with very frequent recurrences (≥10 episodes per year), as this regimen is less effective than other dosing options 1
• Avoid high-dose valacyclovir (8 g/day) in immunocompromised patients due to association with hemolytic uremic syndrome or thrombotic thrombocytopenic purpura 3, 1
• Do not expect complete prevention of transmission or asymptomatic shedding with suppressive therapy 1
• Continuous suppressive acyclovir has minimal toxicity, and viral resistance during suppressive therapy has not been a significant problem in clinical practice 6

Duration and Re-evaluation

• Continue suppressive therapy for up to 12 months, then discontinue to reassess recurrence patterns 1
• The extent to which suppressive therapy prevents HSV transmission remains unknown 1
• Pretreatment frequencies of recurrence typically return after discontinuation of treatment 7