Karen speaks up about some very good points. I would like to add that you need to find a psychiatrist (a pediatric psychiatrist would be wonderful). Personally, I would spend the extra money to see a professional in this area, like if it wasn't covered by our health insurance. I'm lucky that our health insurance helps out a lot.
Our doctor (the child psychiatrist) explained how Xmg of this med was a low dose and how much was a high dose and work with me on getting up to just the right amount for my child. If the doctor you are talking to doesn't provide this, ASK!!! It is your right to ask! Strattera is one of the stimulant meds which is fast acting and doesn't stay in the kid's system for long periods. Yes, giving your child the doses as recommended will not cause anything that your child won't bounce back from, if it's not needed. And plan a trip to the school. Ask the teacher(s) for a time when you can observe her, possibly through a door window so she is not distracted with seeing that you are there. This is HIGHLY useful to YOU.
I have three "high-needs" boys and I have had this very experience. I'm still amazed at how each can act one way around me and quite another in a different situation or place. I have had to give up an hour here and an hour there for 1) visits to the school, 2) conferences with the teacher(s), and visits with the doctor(s). But this investment of my time, I think, has been extremely valuable for my kids. I know I'm lucky to be able to put in these hours being a part-time working mom.
Questions you could be asking the teachers are a) in what way(s) is your daughter not keeping up with the other students? b) how much time does the teacher spend just with your little one because she needs the extra direction or help compared to the other children in the classroom? and c) what are their reasons (specifically!) for wanting to have her repeat kinder next year.
I was surprised, while my oldest boy started school, at how much I could really be helping at home with little work at reinforcing subjects being covered in school. Like, I see a red sign/billboard, can you point to it? Or help me find something in this room that is grey (I would have a grey piece of paper for illustration). Counting people in the family! Counting chairs at the table. etc, etc.
Anyway, wish you good luck with this! Remember: you are being a great mom because you worry about this and want to do the best that is possible for your daughter!