Not to be used in patients w/ type 1 DM or diabetic ketoacidosis. Lactic acidosis; inadequately controlled diabetes, ketosis, prolonged fasting, any conditions associated w/ hypoxia; CV collapse (shock), acute CHF & MI, other conditions associated w/ hypoxemia; acute conditions eg, dehydration, severe infections, hypoperfusion; risk of vol depletion, hypotension &/or electrolyte imbalance; GI illness, heat stress, severe infections; known CV disease; history of hypotension; urosepsis, pyelonephritis; necrotising perineum fasciitis/Fournier's gangrene; patients w/ low β-cell function reserve; insulin dose reduction; reduced caloric intake; increased insulin requirements due to infection, illness or surgery; loss of blood glucose control; cardiac failure (NYHA I-IV). Discontinue use prior to or during iodinated contrast agent administration & not to be reinstituted until 48 hr afterwards. Discontinue use 48 hr before elective surgery w/ general, spinal or epidural anaesth. Assess & monitor renal function prior to & at least annually thereafter. Regularly evaluate serum electrolytes & ketones, blood glucose, pH, lactate, pyruvate & metformin levels. Hypoglycemia w/ insulin & insulin secretagogues eg, sulfonylureas. Concomitant use w/ antihypertensive, diuretics, NSAIDs; drugs causing lactic acidosis. Interference w/ 1,5-anhydroglucitol assay. Acute or chronic excessive alcohol intake. Counsel patients on routine preventive foot care. May affect ability to drive & use machines. Not to be used in moderate & severe renal impairment or end-stage renal disease. Not to be used in severe hepatic impairment; clinical or laboratory evidence of hepatic disease. Not to be used during 2nd & 3rd trimesters of pregnancy & lactation. Ped & adolescent patients. Elderly.