Do you administer antiviral medications to adults with varicella (chickenpox)?

From the Guidelines

Antiviral medications are typically recommended for adults with chickenpox, as adults generally experience more severe symptoms and have a higher risk of complications than children. The preferred antiviral is acyclovir, usually prescribed at 800 mg orally five times daily for 7-10 days 1. Alternative antivirals include valacyclovir (1000 mg three times daily for 7 days) or famciclovir (500 mg three times daily for 7 days) 1. Treatment should ideally begin within 24-72 hours of rash onset for maximum effectiveness. Antivirals are particularly important for adults with compromised immune systems, pregnant women, those with severe disease, and patients with chronic skin or lung conditions.

Some key points to consider when treating adults with chickenpox include:

• The severity of the disease and the risk of complications, such as secondary bacterial or fungal infections, which can be reduced with antiviral therapy 1
• The importance of starting treatment within 24-72 hours of rash onset to maximize effectiveness 1
• The need for supportive care, including acetaminophen for fever, antihistamines for itching, and proper skin care to prevent secondary infections
• The potential for antiviral resistance, particularly in patients with a history of repeated antiviral therapy for recurrent disease 1

It's worth noting that the most recent and highest quality study, published in 2021, recommends antiviral therapy for all immunocompromised patients with varicella infection, and suggests that treatment should be prescribed within 72 hours of rash onset and continued for a minimum of 7-10 days 1. Overall, the use of antiviral medications in adults with chickenpox can significantly reduce the severity and duration of symptoms, decrease the risk of complications, and improve quality of life.

From the FDA Drug Label

Adults and Children over 40 kg: 800 mg 4 times daily for 5 days.

• Treatment of Chickenpox in Adults: The recommended dose of acyclovir for adults with chickenpox is 800 mg 4 times daily for 5 days.
• Initiation of Therapy: Therapy should be initiated at the earliest sign or symptom of chickenpox.
• Efficacy of Late Therapy: There is no information about the efficacy of therapy initiated more than 24 hours after onset of signs and symptoms 2.

From the Research

Antiviral Treatment for Chickenpox in Adults

• Antiviral therapy, such as acyclovir, is effective in treating chickenpox in adults, particularly when administered early in the course of the infection 3, 4, 5.
• Intravenous acyclovir is recommended for immunocompromised patients, neonates, and adults with severe complications, such as varicella pneumonia 3, 5.
• Oral acyclovir can be effective in treating chickenpox in otherwise healthy adults and adolescents, but it must be started within 24 hours of the onset of the rash 3, 5.
• The dosage of acyclovir for treating chickenpox in adults is typically higher than that required for treating herpes simplex virus (HSV) infections, with recommended doses of 500 mg/m2 or 10 mg/kg every 8 hours intravenously, or 800 mg five times a day orally 3.

Benefits and Safety of Antiviral Treatment

• Antiviral treatment can reduce the severity and duration of chickenpox symptoms, as well as decrease the risk of complications, such as pneumonitis and disseminated disease 4, 6, 7.
• Acyclovir has a high therapeutic index and a good safety profile, but caution is advised when using it in pregnancy 5.
• The effectiveness of antiviral treatment in preventing postherpetic neuralgia is unclear 3.

Guidelines for Antiviral Treatment

• The decision to treat chickenpox with antivirals should be based on the individual's risk factors, such as age, immune status, and presence of complications 4, 5.
• Guidelines for the treatment of chickenpox in adults have been developed by specialist physicians and are available to guide emergency physicians and general practitioners in their decision-making process 4.