During a well-child visit, an infant 1 month old treated with parenteral acyclovir for neonatal herpes currently takes oral acyclovir. What should the nurse practitioner do?

• A. Obtain regular absolute neutrophil counts.
• B. Perform routine skin cultures for herpes simplex virus.
• C. Reinforce the need to give acyclovir indefinitely.
• D. Stop the oral acyclovir at 2 months of age.

Answer: (A)

Acyclovir in neonates can affect the bone marrow, leading to neutropenia. Even after transitioning from parenteral to oral therapy, regular monitoring of the absolute neutrophil count helps detect this toxicity early and guides safe continuation of treatment. That’s why the best action at a well-child visit is to obtain regular absolute neutrophil counts. Routine skin cultures aren’t needed unless new lesions appear, reinforcing indefinite therapy isn’t indicated without safety data, and stopping at a set age isn’t appropriate without current lab and clinical status. Monitoring labs ensures the infant remains safe while still on antiviral therapy.