Sue, When I first started Mestinon and it was the only drug I was taking (January 2009) I had lots of twitching. It even caused a pulling sensation around the corners of my mouth and affected me speaking. I almost felt like I was having a seizure. The nurse said Mestinon can cause all of that. I was told to stop the Mestinon when they put me on 60 mg. of Prednisone. I was slowly taken down to 20 mg. and added CellCept. She said yesterday that starting to take the Mestinon with the CellCept now may even work better. So, I am giving it a try.