Fatal Metformin Intoxication: A Case Report in a Young Adult with Intellectual Disability

Metformin-associated lactic acidosis is a rare but life-threatening complication of a widely prescribed therapy for type 2 diabetes. This case report describes a fatal outcome following intentional metformin intoxication in a vulnerable patient with intellectual disability. The patient was initially asymptomatic but shortly became unresponsive and died. The cause of death was established as metformin intoxication through postmortem toxicological analysis, which revealed a cardiac blood metformin concentration of 53.60 μg/mL. This finding was supported by the presence of metformin tablet debris in the gastric contents and the exclusion of alternative causes, including traumatic injury and co-ingested sulfonylureas. This case underscores the critical need for early detection of metformin toxicity and highlights the essential role of clinical toxicology in guiding postmortem diagnosis.