My daughter is 10 with SWCAH.  When she was younger, she often became carsick.  Sometimes we could anticipate the need to vomit, sometimes not-you know how that goes!  Our ped endo told us to get her out of the car into fresh air, have her sip water, take a triple dose of cortef by mouth.  If she holds that, give some saltine crackers.  That usually worked and she never vommitted twice.  Different story if it’s vommitting related to a virus, esp if there’s a fever.  With our daughter, I inject immediately in that case.  Anyways, best to follow the ped endo’s instructions.  That’s our experience.  Good luck and I hope he has fun!

 

Pamela