Lactic acidosis

excessive plasma acidity due to an accumulation of lactic acid. This may be caused by a variety of illnesses, including heart failure or severe dehydration. It can also be caused by the accumulation of BIGUANIDE drugs used for treating type 2 DIABETES MELLITUS , particularly when kidney failure is present. Biguanides (see METFORMIN ) should therefore not be used to treat patients who also have kidney disease or heart failure or who are dehydrated.