[A case of lactic acidosis caused by buformin in an oldest elderly diabetic patient].

A 93-year-old male was urgently admitted to our hospital with dyspnea and disturbance of consciousness. The patient had been visiting a general physician regularly for ten years, for treatment of type 2 diabetes. He had been treated with glibenclamide and voglibose, until voglibose was replaced with buformin 3 months before admission.