Metformin-associated Lactic Acidosis Induced by Excessive Alcohol Consumption.

A 65-year-old man with type 2 diabetes who was being treated with metformin developed lactic acidosis following excessive alcohol consumption. While an impaired renal function is a major risk factor for metformin-associated lactic acidosis (MALA), the patient's basal renal function was normal. Alcohol misuse reduces lactate clearance by utilizing nicotinamide adenine dinucleotides for ethanol oxidation, thereby promoting vulnerability to MALA. Nevertheless, as MALA in individuals with a normal renal function is extremely rare, the clinical picture of alcohol-induced MALA is unclear. We delineate the clinical picture and discuss the pathogenesis of alcohol-induced MALA based on our experience and previous case reports.