Multivitamins for Growing Boys...

My older boy is growing rather rapidly in recent months. I didn't realize that he was as tall as I am until a friend mentioned it. All along, I had thought that he only reached my eye brows. With this growth spurt, I supposed I must switch his kiddie mutivitamins to a different one. Do you know what is the best multivitamins for growing boys? Whilst we are on the topic of growing boys... my younger boy somehow doesn't seem to be growing at all! I am wondering if I should supplement his diet with nutritional drinks on top of the multivitamins. What do you think?