Sometimes i take ritalin and it works fine. But sometimes it totally drains and exhausts me(like now). I dont understand why this happens, does anyone know what would cause this?

OK, I know I'm not really answering your question, but different things could be affecting you. How long have you been taking ritalin? Also, are there certain times of the month you feel tired?

I do the same thing. I have heard some people say it has to do with whether you were already a little tired for some reason. Then, they said, it can make you tired but if not then it doesn't. It doesn't make sense to me either :)

I'm on concerta and I find the same thing. If I'm not already tired, I feel fine, if I'm tired already, then it puts me to sleep. I've never been a napper, so for me, when I can nap, it's a help! :D