What is the treatment and dosage for Acyclovir (antiviral medication) in herpes simplex virus infections?

From the Guidelines

Acyclovir is the standard antiviral treatment for herpes simplex virus (HSV) infections, with dosing varying by infection type and severity, and the most practical treatment regimens should be prioritized for patient adherence. For first-episode genital herpes, the recommended dosage is 400 mg orally three times daily for 7-10 days, or 200 mg five times daily 1. For recurrent episodes, 400 mg three times daily for 5 days or 800 mg twice daily for 5 days is effective. Severe cases requiring hospitalization may need intravenous acyclovir at 5-10 mg/kg every 8 hours for 5-7 days. For oral herpes (cold sores), 400 mg orally five times daily for 5 days is recommended.

Key Considerations

• Suppressive therapy for frequent recurrences (more than 6 episodes yearly) consists of 400 mg twice daily continuously.
• Acyclovir works by inhibiting viral DNA synthesis, preventing HSV replication.
• Treatment is most effective when started within 72 hours of symptom onset.
• Patients should complete the full course even if symptoms improve, stay hydrated, and be aware that acyclovir reduces but doesn't eliminate viral shedding.
• Dose adjustments are necessary for patients with renal impairment, and common side effects include nausea, headache, and dizziness.
• If lesions persist in a patient receiving acyclovir treatment, resistance of the HSV strain to acyclovir should be suspected, and alternate therapy such as foscarnet or topical cidofovir gel may be effective 1.

Recent Guidelines

The 2021 Centers for Disease Control and Prevention sexually transmitted infections treatment guidelines recommend prioritizing dosing strategies that are most feasible for patient adherence 1. Although episodic and suppressive therapy for genital HSV-1 infection have not been studied as comprehensively as for genital HSV-2, the same medication dosages and frequencies are recommended for genital HSV-1 infection.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Acute Treatment of Herpes Zoster: 800 mg every 4 hours orally, 5 times daily for 7 to 10 days. Genital Herpes: Treatment of Initial Genital Herpes: 200 mg every 4 hours, 5 times daily for 10 days. Chronic Suppressive Therapy for Recurrent Disease: 400 mg 2 times daily for up to 12 months, followed by re-evaluation Intermittent Therapy: 200 mg every 4 hours, 5 times daily for 5 days. Therapy should be initiated at the earliest sign or symptom (prodrome) of recurrence.

The treatment and dosage for Acyclovir in herpes simplex virus infections are as follows:

• Initial Genital Herpes: 200 mg every 4 hours, 5 times daily for 10 days
• Chronic Suppressive Therapy: 400 mg 2 times daily for up to 12 months
• Intermittent Therapy: 200 mg every 4 hours, 5 times daily for 5 days Therapy should be initiated at the earliest sign or symptom of recurrence 2.

From the Research

Treatment and Dosage for Acyclovir in Herpes Simplex Virus Infections

• The treatment for herpes simplex virus (HSV) infections typically involves antiviral medications such as acyclovir, valacyclovir, and famciclovir 3, 4, 5, 6, 7.
• Acyclovir is an effective medication for the treatment of HSV infections, and its prodrug valacyclovir has been shown to have improved bioavailability and efficacy in suppressing recurrent episodes of genital herpes 3, 4.
• The dosage of acyclovir for the treatment of HSV infections can vary depending on the severity and frequency of outbreaks, as well as the patient's immune status 3, 6.
• For example, a study comparing valacyclovir and acyclovir for the treatment of first-episode genital herpes found that valacyclovir 1000 mg twice daily was as effective as acyclovir 200 mg five times daily 4.
• Another study found that valacyclovir 500 mg daily was effective in suppressing recurrent episodes of genital herpes in immunocompetent individuals 3.

Comparison with Other Antiviral Medications

• Valacyclovir has been compared to famciclovir in several studies, with results suggesting that valacyclovir may be more effective in suppressing genital herpes and associated shedding 5.
• A review of the treatment of herpes simplex infections found that valacyclovir, acyclovir, and famciclovir are all effective medications for the treatment of HSV infections, but that the choice of medication and dosing regimen can depend on various factors, including the patient's immune status and the severity and frequency of outbreaks 6.
• Valacyclovir has also been shown to be effective in the treatment of herpes zoster, and may be more effective than acyclovir in hastening the healing of zoster-associated pain and postherpetic neuralgia 7.

Dosage and Administration

• The dosage of valacyclovir for the treatment of HSV infections can vary depending on the severity and frequency of outbreaks, as well as the patient's immune status 3, 6.
• For example, valacyclovir 500 mg daily is recommended for the suppression of recurrent episodes of genital herpes in immunocompetent individuals 3.
• Valacyclovir 1000 mg twice daily has been shown to be effective in the treatment of first-episode genital herpes 4.
• The medication should be taken as directed, and patients should be advised to consult their healthcare provider if they experience any adverse effects or have concerns about their treatment regimen 3, 6.