I never get sick on rides. I do TOT and RNRC several times in a row when I get the chance.
However, just in case, I took dramamine the first time (uh, only time) I went on MS.
It did nothing. Now that's just me, but the pills did not do me any good.
I almost passed out and had to sit in the bench by the dressing rooms at Mouse Gear for almost an hour before I could get up and walk again.
Again, that's just me, but it ruined my day. Lots of people on here have not had problems, though. I've also heard a lot of people recommend those bracelets that are supposed to help with motion sickness. I'm sure someone will post with more info about them.
Good Luck1