Varicella treatment in immunocompromised patients or those older than 12 years should include which antiviral?

• A. Valacyclovir
• B. Acyclovir
• C. Famciclovir
• D. No antiviral therapy

Answer: (B)

Varicella in patients with immune suppression or in older children/adults can progress to severe, disseminated disease, so the goal is rapid suppression of viral replication with an agent proven to be effective against VZV. Acyclovir fits this need best because it reliably inhibits the viral DNA polymerase after activation by viral thymidine kinase, quickly reducing viral replication. In immunocompromised patients or when disease is more likely to be severe, intravenous acyclovir is preferred because it achieves higher systemic and tissue concentrations, helping prevent serious complications such as varicella pneumonia or encephalitis. Typical dosing for serious or hospitalized cases is an IV regimen tailored to renal function, often 10 mg/kg every 8 hours, for about 7 to 10 days, with adjustments as needed for kidney function. Early treatment within the first 24 hours of rash onset improves outcomes.

While other antivirals like valacyclovir and famciclovir have good oral bioavailability and can be used in milder cases, they have less established efficacy data in immunocompromised patients, where the risk of progression warrants the strongest option with proven benefit—intravenous acyclovir. Not using antiviral therapy in this high-risk group is not appropriate due to the potential for serious complications.