Dude, I tried everything and the only thing that gave me a little bit of relief was taking two colace every day. But still, that relief was minimal. I finally got past the worst of the m/s, laid off the zofran, started eating salads again and my body spent the whole day Saturday eliminating what the zofran held on to for the last 3 months. It was a blessing and a curse. I hope you find the magic cure so you don't have to go through that!
Good luck!
Oh, and btw, my OB swears that it's the prenatals that are causing constipation, not zofran. I don't believe him, but they do make prenatals with stool softeners in them. Might want to look for those and give them a try!