Discontinue use if dehydration occurs or if metabolic acidosis is suspected. Lactic acidosis; risk factors for lactic acidosis eg, inadequately controlled diabetes, ketosis, prolonged fasting, any conditions associated w/ hypoxia. Discontinue prior to, during & after 48 hr of iodinated contrast agent administration; 48 hr prior to elective surgery w/ general anaesth. Determine serum creatinine levels prior to & regularly thereafter. Perform usual laboratory tests for diabetes monitoring. Concomitant use w/ antihypertensives, diuretics, NSAIDs; insulin of sulfonyureas. Excessive alcohol intake, hepatic insufficiency. Renal impairment. Pregnancy & lactation. Childn 10-12 yr. Elderly.