OBJECTIVE:Metformin is commonly prescribed as a first-line therapy for type 2 diabetes mellitus (DM), which acts by reducing insulin resistance, hepatic glycogenolysis, gluconeogenesis, and intestinal glucose absorption. Although metformin is generally safe, metformin-induced lactic acidosis (MILA) can occur in the setting of intentional poisoning. We report a case with massive metformin intake, who had persistent lactic acidosis due to renal replacement and other supportive treatments, which led to mortality.

CASE:An 18-year-old female patient was brought to the emergency service by her relatives. She had complaints of nausea and vomiting. She declared that she had intentionally taken 100 tablets of metformin 1000 mg and unknown amount of flunarizine 5 mg, 3 hours prior to her arrival at the emergency service. Metformin-induced lactic acidosis was considered for the patient with high anion gap metabolic acidosis and increased level of lactate. Despite immediate dialysis, the patient’s acidosis worsened, mental status deteriorated, and the patient became hypotensive following the hemodialysis. 1 mEq per kgs sodium bicarbonate (NaHCO3) was administered as well as vasopressor therapy (0.05 mcg/kg/min norepinephrine) was initiated and the patient was handed over to the intensive care unit (ICU) to continue the therapy with continuous veno- venous hemofiltration (CVVHF). On the second day of the patient's ICU stay, despite the continuous supportive treatment, the patient died.

RESULT:Metformin induced lactic acidosis is a well known severe clinical condition, however, It is unclear what minimal dosage is required for toxicity. What’s more, lactic acidosis due to intentional metformin overdose has the highest mortality rates amongst the other causes, and could remain persistent to supporting treatments.