Metformin-related lactic acidosis in patients with acute kidney injury

Metformin is nowadays considered as first-line therapy in individuals with non-insulin dependent diabetes mellitus (NIDDM). Metformin-related lactic acidosis (MALA) occurs more frequently after inappropriate use especially in patients with acute kidney injury (AKI) or chronic kidney disease (CKD). Thus, its prescription in these patients is contraindicated, while the role of dialysis is under evaluation. We describe two cases of severe metformin-related lactic acidosis with underlying acute kidney injury, which were treated with dialysis. In both cases, lactic acidosis occurred on a background of acute decline in renal function, possibly due to drug accumulation. It is interesting that metformin was contraindicated in one case. Lactic acidosis is a rare but potentially fatal adverse effect of metformin, particularly in patients with AKI, which should always be considered in clinical practice. Dialysis seems to contribute significantly to the management of this life-threatening condition and the improvement in outcome.