If I was told the possible side effects, my daughter was dehydrated, and they wanted to give her this drug, I would have asked all kinds of questions. The problem is too many emergency rooms or doctors do not give parents the information they need IMHO to make a decision.
She was given the drug and then sent home where she had the first seizure, rushed back to the hospital, suffered a second seizure and quit breathing, was stabilized and transferred to OU Medical Center.
At least if you knew the side effects, you would be on the lookout for any signicant change in your child.
Sure, you need to know what to look for, and that's a fair criticism, if they weren't told. But from your description, the child was very bad. I have seen some children given some pretty dangerous things in that type of situation because there was no choice.