I have had LEMS for over a year, they tried steroids, IVIG still get ivig every other week) and the mestinon, I was on 30 3 times a day for 8 days, noted nothing at all, they then switched me 60 mg every 6 hours for another 8 days and I got no effect at all. they ended up getting tossed out the window as they were not working.. that is my take on mestinon.