My daughter is 5 months old. She has been taking Kuvan for almost two weeks, so we don't know if she is receptive yet. She hasn't had too many side affects so far. She seems to sleep a lot more which hasn't been a bad thing. It was a hard choice for me to make. I decided that I at least wanted to know if she was receptive and then i could decide if I wanted her on the medication long term. They have shown that there are little to no side affects short term so I don't worry about that part of it. Once I know if it even works for her then I can go from there. Hope that helps
My daughter is 18 months old and has been taking Kuvan for about two months now. She and my son responded. No side effects. But what was even better than my kids being able to tolerate a few more phe's was the improvement in their moods. Both seem much happier and when there is a tantrum it is not sooo extreme.