I've been on Mestinon since 1986 and can tell you that it's a hard drug on the system, even if taken with milk or crackers. (Hopefully you won't ever have to take CellCept!). It's something you'll have to get used to and perhaps adjust some of your eating habits (I had to say goodbye to spicey food...). And as Lois said, twitching can be a symptom of overdosing on Mestinon -- that happens to me, too.