Diabetic ketoacidosis, diabetic pre-coma; severe infection, before and after operation or with serious trauma; gastrointestinal obstruction or predisposed to it; renal failure or renal dysfunction [creatinine clearance (CrCl) <60 mL/min]; acute conditions with the potential to alter renal function eg, dehydration, severe infection, shock, IV administration of iodinated contrast agents, acute or chronic disease which may cause tissue hypoxia eg, cardiac or respiratory failure, recent myocardial infarction, shock; hepatic insufficiency, acute alcohol intoxication, alcoholism.