[Accumulation of Metformin-associated Lactic Acidosis].

Lactic acidosis has been associated with the use of metformin since its introduction. The cause, however, is highly controversial. The incidence of metformin-associated lactic acidosis (MALA) is quoted at 3,0 to 16,7 cases per 100 000 patient-years according to current studies. The link between metformin and lactic acidosis in metformin therapy has been suggested to be causal and therefore, the use of metformin was restricted to type 2 diabetic patients without renal impairment. Recent studies, however, show an acceptable use and no increased incidence of lactic acidosis in chronic mild to moderate renal insufficiency, respectively.  Case report.  4 Patients were admitted to the Limmattal Hospital for treatment of severe lactic acidosis under Metformin-treatment during 9 months. These type 2 diabetic patients with previously normal renal function presented with remarkable similar clinical history of acute diarrhoea and vomiting. On the day of admission, acute renal failure (AKIN III) was found and haemofiltration was required in all patients. After a maximum duration of 24 hours of haemofiltration, the metabolic acidosis was corrected and the estimated glomerular filtration rate improved. On day 7 of hospitalization, two patients had a normal and two patients an impaired renal function (stage III or IV, respectively).  In case of diarrhoea and vomiting in patients with type 2 diabetes under metformin-treatment, the active search for lactic acidosis is essential, independently of the previous renal function. An early diagnosis and therapy of MALA allows a good prognosis.