Nothing wrong with getting them from abroad. FDA approved is bull in my opinion. If it's from an online pharmacy with a decent reputation online, and they sell branded medicines there isn't that much to worry about. I wouldn't just go for any pharmacy, it should be a reputable one.
What would be the point in selling a fake anti emetic, it's really not big business considering they already have a solid business model of selling prescription drugs to other countries with more restrictions. They literally have customers in their lap, faking it makes no business sense because your rep goes down the toilet completely unnecessarily.