Metformin-associated lactic acidosis refractory to hemodialysis in the setting of concomitant alcohol intoxication

Abstract

Metformin is widely used as a first-line therapy for type 2 diabetes mellitus (T2DM). Although metformin is generally safe, metformin-associated lactic acidosis (MALA) can occur. Early recognition and treatment of MALA is crucial to prevent complications and mortality. We present a case of 51-year-old man with hypertension and T2DM who was brought to our emergency room with altered mental status after ingesting 18,000 mg metformin and binge drinking of alcohol the previous night. Laboratory blood analysis showed 22.8mmol/L lactic acid, 36.7 mmol/L anion gap, 6 mmol/L bicarbonate, 18 mg/dL blood urea nitrogen, and 2.5mg/dL creatinine. Based on blood analysis results, the patient was diagnosed with MALA and acute kidney injury. He underwent several rounds of hemodialysis but ultimately did not survive. Immediate hemodialysis is indicated for MALA in patients with significant comorbidities. However, hemodialysis may be ineffective to counteract metformin overdose in conjunction with alcohol intoxication. In such cases, depletion of NAD+ stores can result in an inability to clear lactic acid. Severe lactic acidosis associated with metformin treatment has an increased mortality rate in the presence of comorbidities that decrease lactate and metformin clearance.