Don't bother with medication
I suffered a little with this problem. Medication probably wont fix it and you need to be so careful with what you take anyhow.
The instigator for me was yaw so I'm sure that you do anyhow but keep the ball in the middle during turns. Before flight you must eat something a couple of hours earlier. Sip water when you get a chance during the flight.
You get used to it fairly quickly and you will soon be doing stalls and spins. A lot of the problem occurs when you are thinking about feeling unwell. I suddenly realised that it wasn't bothering me any longer and forgot all about it.
I find full motion sims more of a problem...the yaw movement in those especially whilst 'taxying' is distinctly unpleasant.
Good luck.