Massive Metformin Overdose in Two Subjects with Suicidal Behavior: Brief Communication

Lactic acidosis is a well-recognized side effect of metformin, especially in patients with renal failure. Only a few cases of deliberate self-poisoning with metformin have been described in the literature. The mechanism of metformin-associated lactic acidosis is complex. In the absence of acute overdose, metformin-associated lactic acidosis rarely develops in patients without comorbidities such as renal or hepatic insufficiency or acute infection. We report two patients who had a large dose of metformin in an attempt to harm themselves and presented with lactic acidosis. In our experience, metformin intoxication may lead a high anion gap metabolic acidosis after a suicide attempt. Sodium bicarbonate infusion is able to correct the acid-base metabolism sufficiently in subjects with normal renal functions.