- Illness, incompatible with metformin treatment, in particular those associated with a risk of hypoperfusion or hypoxia (not limited to): acute or chronic renal failure (creatinine clearance < 60 ml/min, according to the MDRD formula); lactic ketoacidosis; septic shock; congestive heart failure; respiratory distress; liver failure; chronic alcoholism; uncontrolled seizures; age > 80 years; allergy/hypersensitivity to metformin.