Why Do Biguanides Cause Lactic Acidosis?

Biguanides also decrease hepatic metabolism of lactate and have a negative ionotropic effect on the heart, both of which elevate lactate levels (11). Metformin dose, along with the duration of exposure from accumulation in patients with decreased renal clearance, can cause lactic acidosis (3).

Can metformin cause elevated lactic acid?

Summary. Metformin rarely, if ever, causes lactic acidosis when it is used as labeled. Metformin is associated with lactic acidosis in patients with conditions that can themselves cause lactic acidosis (heart failure, hypoxia, sepsis, etc.).

How does metformin increase lactate?

Metformin, along with other drugs in the biguanide class, increases plasma lactate levels in a plasma concentration-dependent manner by inhibiting mitochondrial respiration predominantly in the liver.