Hypersensitivity to metformin.
Patients with renal and hepatic failure which may also result from conditions eg, cardiovascular collapse (shock), acute myocardial infarction and septicaemia.
Congestive heart failure requiring pharmacologic treatment.
Acute or chronic metabolic acidosis, including diabetic ketoacidosis with or without coma. Diabetic ketoacidosis should be treated with insulin.
Dehydration, acute or chronic alcoholism or any other condition which may predispose to lactic acidosis.