What is the dosage of Valacyclovir (Valovir) for treating chickenpox (varicella)?

From the Guidelines

Valacyclovir is not the preferred treatment for chicken pox, and its use should be determined on a case-by-case basis, with acyclovir being the standard antiviral medication used for this condition. For the treatment of chicken pox, the typical dosage of acyclovir is 20 mg/kg (maximum 800 mg) taken 4 times daily for 5 days in children, or 800 mg 5 times daily for 7 days in adults 1. However, if valacyclovir must be considered, the dosage would be 1 gram orally twice a day for 7-10 days, as indicated for other conditions, but it's crucial to note that this is not the standard treatment for chicken pox and should only be considered after consultation with a healthcare provider.

Key Considerations

• Treatment should be started within 24 hours of rash onset for maximum effectiveness.
• Antiviral treatment is most beneficial for patients at higher risk of complications, including adults, pregnant women, immunocompromised individuals, and those with severe disease.
• Supportive care with fever control, hydration, and anti-itch treatments remains important regardless of antiviral use.

Dosage and Administration

• Acyclovir: 20 mg/kg (maximum 800 mg) taken 4 times daily for 5 days in children, or 800 mg 5 times daily for 7 days in adults.
• Valacyclovir (if considered): 1 gram orally twice a day for 7-10 days, but this is not FDA-approved for chicken pox.

Patient Selection

• Patients at higher risk of complications from chicken pox should be prioritized for antiviral treatment.
• Consultation with a healthcare provider is necessary before initiating valacyclovir for chicken pox treatment due to its non-standard use for this condition.

From the FDA Drug Label

The use of VALTREX for treatment of chickenpox in pediatric subjects aged 2 to less than 18 years is based on single‑dose pharmacokinetic and multiple‑dose safety data from an open‑label trial with valacyclovir and supported by safety and extrapolated efficacy data from 3 randomized, double‑blind, placebo‑controlled trials evaluating oral acyclovir in pediatric subjects The single‑dose pharmacokinetic and multiple‑dose safety trial enrolled 27 pediatric subjects aged 1 to less than 12 years with clinically suspected VZV infection. Each subject was dosed with valacyclovir oral suspension, 20 mg/kg 3 times daily for 5 days Based on the pharmacokinetic and safety data from this trial and the safety and extrapolated efficacy data from the acyclovir trials, oral valacyclovir 20 mg/kg 3 times a day for 5 days (not to exceed 1 gram 3 times daily) is recommended for the treatment of chickenpox in pediatric patients aged 2 to less than 18 years

The recommended dosage of valacyclovir for the treatment of chickenpox is 20 mg/kg 3 times a day for 5 days, not to exceed 1 gram 3 times daily, for pediatric patients aged 2 to less than 18 years 2.

From the Research

Valovir Dosage for Chicken Pox

• The dosage of valaciclovir (Valovir) for chicken pox is not explicitly stated in the provided studies, but the dosage for herpes zoster can be used as a reference 3, 4.
• For herpes zoster, the recommended dosage of valaciclovir is 1000 mg three times daily for 7 days 3, 4.
• Aciclovir, which is the active antiviral component of valaciclovir, has been used to treat chicken pox, with a dosage of 800 mg five times daily for 5-10 days 5, 6.
• It is essential to note that the dosage and treatment duration may vary depending on the patient's age, immune status, and severity of the disease.

Administration and Precautions

• Valaciclovir should be administered as soon as possible after symptoms appear, ideally within 72 hours of rash onset 3.
• Adequate hydration and urine flow must be maintained during treatment with aciclovir or valaciclovir, and impaired renal function requires regulation of dosage downward 5.
• The safety profile of valaciclovir is similar to that of aciclovir, with nausea and headache being the most commonly reported adverse events 3, 4.

Treatment Guidelines

• Symptomatic treatment is usually adequate for chicken pox, but in some cases, antiviral drugs like aciclovir or valaciclovir may be necessary, especially for immunocompromised patients or those with severe disease 7, 6.
• The use of corticosteroids in chicken pox treatment remains a topic of debate, and their use should be carefully considered on a case-by-case basis 7.