<prompt> In the management of diabetes mellitus, lactic acidosis is caused by which of the following?TolbutamideGlipizidePioglitazoneMetformin  <response>: Metformin:- SE: Lactic acidosis Megaloblastic anemia To prevent lactic acidosis, Metformin is to be avoided in high risk patients: Old patients Pt. with renal failure Pt. with liver diseases CHF Tolbutamide 1st gen. Sulfonylureas - se - Hypoglycemia, weight gain. Glipizide 2nd gen. Sulfonylureas - se - Hypoglycemia Pioglitazone - acts by stimulating PPAR-g - reversal of Insulin resistance, se - hepatotoxic, edema and Increased risk of urinary bladder cancer 