Suspect lactic acidosis in diabetic patients w/ metabolic acidosis lacking evidence of ketoacidosis eg, ketonuria & ketonemia. Discontinue immediately in patients w/ lactic acidosis; CV collapse (shock), acute CHF, acute MI & other conditions characterized by hypoxemia. Patients w/ serum creatinine level above upper limit of normal for their age should not receive Forbetes XR. Carefully titrate in elderly to establish min effective dose. Monitor renal function before initiation of therapy & at least annually thereafter; regularly in elderly ≥80 yr. Concomitant use w/ cationic drugs eliminated by renal tubular secretion. Temporarily discontinue at the time of or prior to radiologic studies involving use of intravascular iodinated contrast materials or any surgical procedure except minor procedures. Acute or chronic excessive alcohol intake. Patient w/ previously well controlled type 2 DM who develop laboratory abnormalities or clinical illness should be evaluated promptly for evidence of ketoacidosis or lactic acidosis. Hypoglycemia can occur when caloric intake is deficient, strenuous exercise is not compensated by caloric supplementation, or during concomitant use w/ other glucose-lowering agents (eg, sulfonylureas & insulin) or ethanol. A temporary loss of glycemic control may occur during fever, trauma, infection, or surgery. Renal & hepatic impairment. Not recommended for use in pregnancy. Lactation. Childn. Elderly, debilitated, or malnourished patients & w/ adrenal or pituitary insufficiency or alcohol intoxication are particularly susceptible to hypoglycemic effects.