Hypersensitivity to Metformin or to any of the excipients.
Any type of metabolic acidosis (such as lactic acidosis, diabetic ketoacidosis).
Severe renal failure or renal dysfunction (creatinine clearance or GFR <30 mL/min).
Acute conditions with the potential to alter renal function such as: dehydration, severe infection, shock, intravascular administration of iodinated contrast agents (see Precautions).
Disease (especially acute disease, or worsening of chronic disease) which may cause tissue hypoxia such as unstable congestive heart failure, respiratory failure, recent myocardial infarction or shock.
Elective major surgery (see Precautions).
Hepatic insufficiency, acute alcohol intoxication, alcoholism.