The doctors here put me on Metformin variants twice, the first, serious stomach cramps, vomiting and diarrhoea, that after 1 tablet. The second occasion, serious stomach pains to the extent of having morphine..seriously it was that bad. However they persisted, and second pill, still was sti on morphine, getting above diarrhoea again and all muscles locking up, could not see, could not talk, had difficulty breathing. Anyway that rubbish was stopped and after 4 days allowed to go home, could not focus my eyes, that lasted for about 6 weeks before I could ride my motorcycle again, severe stomach pains and aformentioned side effect lasted about a week, was very weak.
So, as the doctor said, "we won't try THAT again!"