Metformin is infamous for its effect on the gut - when I tried it I was unable to leave the house some days, but other people find it does become better with time, I found it got worse, and I got pain, itching all over, muscle twitching and just had to give it up. I tried all ways to take it, before eating, during, after with a large glass of water, and there were sometimes intervals of half a day when it seemed better, but the next tablet brought it all full on again. I think it really is just a matter of luck if you can take it or not, so the only way would be to try it, but not when you have appointments to keep.