I've given IV decadron PO countless times to peds pts. I've never seen a PO form of it and usually with peds we try PO if they're stable enough to take it (mixed with juice, it tastes horrible alone). Decadron is used over prednisolone because it's more potent. As far as Zofran, I've never given IV preparations PO. But again, with peds I would sometimes have to melt an ODT in water and give it to the pt through a syringe. Maybe some places just use the IV preparation instead...