A newborn diagnosed with phenylketonuria (PKU) is placed on a milk substitute, Lofenalac. The mother asks the nurse how long her infant will be taking this. Which of the following responses would be...

A newborn diagnosed with phenylketonuria (PKU) is placed on a milk substitute, Lofenalac. The mother asks the nurse how long her infant will be taking this. Which of the following responses would be most appropriate?

1. “Until the infant is taking solid foods well.”

2. “Until the child has stopped growing.”

3. “Until the phenylalanine level remains below normal for 6 months.”

4. “Probably for a long time, but it's not definitely known.”