What is the recommended daily dose of acyclovir (antiviral medication) for an adult patient with a normal immune system and recurrent herpes simplex virus (HSV) infections?

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Daily Acyclovir for HSV Suppression

For daily suppressive therapy of recurrent HSV in immunocompetent adults, acyclovir 400 mg orally twice daily is the recommended regimen. 1, 2

Standard Suppressive Dosing

  • Acyclovir 400 mg orally twice daily is the primary recommended dose for chronic suppressive therapy 1, 2
  • An alternative regimen of acyclovir 200 mg orally 3-5 times daily can be used to identify the lowest effective dose for individual symptom relief 1
  • The FDA label confirms 400 mg twice daily for up to 12 months, followed by re-evaluation 2

Indications for Suppressive Therapy

  • Suppressive therapy is most appropriate for patients with frequent recurrences (≥6 episodes per year) 1
  • Daily suppression reduces recurrence frequency by ≥75% in patients with frequent outbreaks 1
  • In clinical studies, 73% of patients remained completely symptom-free on suppressive therapy, with another 14% experiencing only mild symptoms 3

Duration and Re-evaluation

  • Safety and efficacy are documented for continuous daily acyclovir therapy for up to 6 years 1
  • After 1 year of continuous suppressive therapy, discontinuation should be discussed to reassess the patient's recurrence rate, as frequency naturally decreases over time in many patients 1, 2
  • Upon withdrawal, 69% of patients experience relapse within 1-4 weeks, typically returning to their pre-treatment recurrence pattern 3

Important Limitations and Caveats

  • Suppressive acyclovir reduces but does not eliminate asymptomatic viral shedding, so the extent to which it prevents HSV transmission remains unknown 1
  • Acyclovir neither eradicates latent virus nor affects subsequent risk, frequency, or severity of recurrences after discontinuation 4
  • Suppressive therapy has not been associated with emergence of clinically significant acyclovir resistance among immunocompetent patients 1
  • Viral susceptibility to acyclovir does not change during long-term treatment 3

Renal Dosing Adjustments

  • For creatinine clearance 0-10 mL/min/1.73m²: reduce to 200 mg every 12 hours 2
  • Hemodialysis patients require an additional dose after each dialysis session due to 60% reduction in plasma concentrations during 6-hour dialysis 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Acyclovir Treatment for Herpes Simplex

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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