My 18 mos old, vomitted 3 times yesterday. I gave the injection at home after the second episode. I called the endo and he said if he did not keep anything down in the next 4 hours then take him to the ER, he did keep some juice down. So we gave him another injection at bedtime w/ juice, and then we woke him at 4:00 am to give him a triple dose of his pill and a bit more juice. So we did not take him to the ER, my Endo an Ped say you are better off treating at home if possible. I was ready to go to the ER if he had continued vomitting, but I would have given the injection first. It is tricky and scary, I had a bad episode w/ my 4 year old w/ CAH. I had but him to bed after only one vomitting, and he was almost in shock the next morning...I learned my lesson and I am much more vigilant at this point.