What is the appropriate dosing for Acyclovir (antiviral medication) in the treatment of Herpes Simplex (HSV) infection?

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From the Guidelines

Acyclovir dosing for herpes simplex should be 400 mg orally three times daily for 7-10 days, or 200 mg five times daily for 7-10 days, as recommended by the most recent and highest quality study 1.

Key Considerations

  • The recommended dosage may vary depending on the severity and frequency of outbreaks, as well as the patient's renal function.
  • For recurrent episodes, treatment should begin at the first sign of symptoms, and patients should complete the full course even if symptoms improve.
  • Suppressive therapy with acyclovir, valacyclovir, or famciclovir can be effective in preventing recurrences, especially for patients with frequent or severe outbreaks 1.

Treatment Options

  • First-episode genital herpes: 400 mg orally three times daily for 7-10 days, or 200 mg five times daily for 7-10 days.
  • Recurrent episodes: 400 mg three times daily for 5 days, or 800 mg twice daily for 5 days, or 800 mg three times daily for 2 days.
  • Suppressive therapy: 400 mg twice daily, or valacyclovir 500 mg daily, or famciclovir 250 mg twice daily 1.

Important Notes

  • Treatment is most effective when started within 72 hours of symptom onset.
  • Patients should maintain adequate hydration while taking the medication.
  • Dose adjustments are necessary for patients with renal impairment.
  • Acyclovir works by inhibiting viral DNA synthesis, preventing the herpes virus from replicating 1.

From the Research

Acyclovir Dosing for Herpes Simplex

  • The dosing regimen for acyclovir in the treatment of herpes simplex infections can be confusing due to competing clinical approaches and evolving dosing schedules based on new research 2.
  • Acyclovir is often used in the treatment of genital herpes, herpes labialis, and herpes zoster, with various dosing regimens available, including intermittent episodic therapy, intermittent suppressive therapy, and chronic suppressive therapy 2, 3, 4.
  • The choice of dosing regimen depends on the clinical characteristics of the patient and their preference, with evidence-based dosing regimens selected based on data from various sources 2.
  • Valacyclovir, a prodrug of acyclovir, has been shown to be effective in the treatment of genital herpes, herpes labialis, and herpes zoster, with a more convenient dosing regimen than acyclovir 3, 4, 5.
  • Comparative studies have shown that valacyclovir may be more effective than famciclovir in suppressing genital herpes and associated shedding, although further comparative trials are needed to confirm these findings 6.

Treatment Options

  • Acyclovir, valacyclovir, and famciclovir are all effective in the treatment of herpes simplex infections, with various dosing regimens available 2, 3, 4, 5.
  • The choice of treatment depends on the clinical characteristics of the patient, their preference, and the severity of the infection 2.
  • Topical and oral antiviral therapy have been shown to be effective in treating herpes labialis, with a significant reduction in episode length and/or healing time 5.
  • Oral acyclovir, valacyclovir, and famciclovir are efficacious and safe for the treatment of the first episode and recurrent genital herpes, and are useful as suppressive therapy for individuals with frequent genital herpes recurrences 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Valacyclovir for the treatment of genital herpes.

Expert review of anti-infective therapy, 2006

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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