I was not able to tolerate the gastrointestional problems when I took Metformin. I have lots of gastro problems to begin with. Metformin is probably one of the most common diabetes drug used today. Perhaps the gastro problems will go away like Shanny said. It is a good drug. Welcome to the forum!I'm new to the forum and new to Metformin. Am on 500 mg 2x day and am feeling tired and sleepy. Is that usual? I guess the gi problems are a given :-(.