I've taken mestinon for a few years now, but have not suffered from nausea except when taking timespan. Still, I nearly always take it with food just in case.

The mestinon is supposed to result in decreased muscle fatigue. It has never seemed to helped 100%. I am more able to function most of the time as long as I take it. Of course I still have to use what energy I have to explain that even though my muscles are tired I am not sleepy.