Do not use in patients w/ type 1 DM or for diabetic ketoacidosis. Lactic acidosis especially in diabetic patients w/ significant renal failure; risk factors eg, poorly controlled diabetes, ketosis, prolonged fasting, excessive alcohol intake, hepatic insufficiency, dehydration, acute conditions associated w/ hypoxia or impacting renal function. Concomitant w/ drugs that can acutely impair renal function eg, antihypertensives, diuretics & NSAIDs. Discontinue if metabolic acidosis is suspected. Discontinue when dehydration, severe infection & hypoperfusion occurs. Promptly discontinue if CV collapse (shock, acute CHF, acute MI, or other conditions characterized by hypoxemia occurs. Temporarily discontinue therapy at the time of or prior to intravascular contrast studies w/ iodinated materials, & w/held for 48 hr & reinstituted only after renal function has been re-evaluated. Temporarily suspend for any surgical procedure (except minor procedures not associated w/ restricted intake of food & fluids). Excessive alcohol intake. Predisposing factors to ketoacidosis eg, low β-cell function reserve resulting from pancreatic disorders (eg, type 1 diabetes, history of pancreatitis or pancreatic surgery), insulin dose reduction, reduced caloric intake or increased insulin requirements due to infections, illness or surgery & alcohol abuse. Evaluate serum electrolytes & ketones, blood glucose, blood pH, lactate pyruvate, & metformin levels in patients w/ type 2 DM. Temporary interruption for patients who develop vol depletion. Concomitant use w/ insulin & insulin secretagogues eg, sulfonylureas. Hypoglycemia especially in elderly, debilitated, or malnourished patients & those w/ adrenal or pituitary insufficiency or alcohol intoxication. Discontinue if Fournier's gangrene is suspected. eGFR persistently <45 mL/min/1.73 m
2, severe renal impairment (eGFR <30 mL/min/1.73 m
2 by MDRD) or ESRD. Assess renal function before initiation of therapy. Avoid in patients w/ clinical or lab evidence of hepatic disease. Do not use during pregnancy (2nd & 3rd trimesters) & lactation. Childn. Elderly.