[Severe lactic acidosis due to metformin: report of 3 cases].

Metformin, an oral antidiabetic drug, is the sole representative of the biguanide class available in France. Because of its beneficial effects on weight and cardiovascular level, it represents the standard treatment for type 2 diabetic obese patients. Lactic acidosis associated with metformin is a rare but serious complication that can occur in these patients, particularly when intercurrent episode promotes the accumulation of this molecule. We report three cases in which the toxic origin of acidosis has been objectified by the plasma assay and intra-erythrocyte metformin. Curative treatment is based on renal replacement therapy, but the main treatment is preventive, requiring compliance with the cons-indications and rules of prescription of this drug.