Clonidine
"My 6 yo tried this after Intuniv failed. It made him constantly tired and irritable, and actually made his impulsiveness worse since he just seemed cranky and emotional all of the time. It also constipated him to the point that ended up with fissures.

It never made a meaningful dent in his ability to concentrate or sit still, and he became more argumentative in school and less willing to comply.

I've yet to meet anyone that these work for, but it sure would be nice if there were a non-stimulant that worked. We're on stimulants now and still haven't found a miracle there, either.

I will say that it didn't affect his appetite, which was nice."