Metformin associated lactic acidosis.

A case of lactic acidosis occurring in association with inappropriate and excessive metformin therapy and a high serum metformin concentration is described. In the other 23 cases of metformin associated lactic acidosis reported to December 1977, renal, cardiovascular and liver disease were common. Although metformin is less likely to cause lactic acidosis than phenformin, neither drug should be prescribed in the presence of renal, hepatic or cardiovascular disease.