[Four cases of fatal lactic acidosis during biguanide therapy (author's transl)]

Four case reports of lactic acidosis occurring during biguanide treatment (2 with phenormin, 2 with buformin) are analysed. Three of the patients died in a toxic state of lactic acidosis, whilst the fourth patient survived lactic acidosis, but died 11 days later due to myocardial infarction. In spite of serum biguanide levels within the therapeutic range, one patient had highly toxic hepatic levels of phenformin (13,500 ng/g tissue). Two factors are essential for the treatment of lactic acidosis: 1. rapid diagnosis: history of biguanide intake; clinical symptoms; acid-base imbalance; rapid lactate determination to establish the diagnosis. 2. therapy: correction of acidosis, insulin and glucose; shock treatment; forced diuresis and/or haemodialysis. From the high numbers of biguanide-treated diabetics and the incidence of lactic acidosis in other countries it can be assumed that this toxic side effect of biguanide treatment occurs relatively frequently in Austria too, but remains largely undetected.