I took one with my prep. They cautioned against taking pills because everything goes straight through you, but since it's sublingual, it should be fine.
Yes, I took several Zofrans when I did prep a few months ago (I checked with the nurse beforehand and she said that was fine). The first time I did prep, I didn't take any Zofran and I did vomit. The second time I did prep, I took Zofran and I didn't vomit, so I'd call that a success.
U can always get zofran that disolves under your tongue.....and I know for sure you can take that before procedure. Good luck tomorrow.....let us know how it goes