METFORMIN-ASSOCIATED LACTIC-ACIDOSIS - TREATMENT WITH HEMODIALYSIS

The biguanide metformin is an oral antihyperglycemic drug widely used in the management oi non-insulin-dependent diabetes mellitus (NIDDM) w hich acts by improving hepatic and peripheral tissue sensitivity to in sulin. Its major drawback is the possibility of developing lactic meta bolic acidosis in patients suffering from renal failure or poor tissue perfusion. However, the incidence is about 10- to 20-fold lower than that reported with phenformin. We report the case of a 84-year-old wom an with NIDDM and hypertension treated with metformin, glibenclamide, enalapril and diuretics who presented with severe high-anion-gap metab olic acidosis: pH 6.9, bicarbonate 5 mmol/L, potassium 7.4 mEq/L and s erum creatinine 6.3 mg/dL. Following a first hemodialysis, performed w ith bicarbonate and glucose dialysate, her plasma lactate level was 16 mmol per liter (normal levels: 1 to 2.2 mmol/L). A second session cor rected these severe acid-base and electrolyte disorders. The rational treatment of metformin-associated lactic acidosis seems to be, apart f rom withdrawing the drug, short consecutive hemodialysis sessions and slow intravenous infusion of 1/6 molar sodium bicarconate, avoiding Na + overload.