Hi everyone. I was on 500 x 2 a day of metformin and because I have an unmanaged cholesterol problem my doctor upped me to 2 tabs of 500 twice a day. After a couple of weeks strange things were happening to me. Not being able to keep my eyes open after dinner, shaking, constipation, itchiness, dizziness etc, to name a few. Yesterday I went back down to 1 tab x daily. How long do you think it will take to have these other side effects wear off. I have an appt. with the doctor but I am fairly concerned. I am the type of person that once you start messing with the medications they never go back to working the way they did to begin with. Anyone else have these experiences?