The antidiabetic agents most likely to cause lactic acidosis is:

Biguanides (phenformin and metformin) increase the insulin action in peripheral tissues and reduce hepatic glucose output due to inhibition of gluconeogenesis. They may decrease plasma glucose by  decreasing the intestinal absorption of glucose. They increase the utilization of glucose by enhancing anaerobic glycolysis. Lactic acid is the end product of anaerobic glycolysis. Most of it is extracted by the liver and utilized for gluconeogenesis. Use of phenformin was associated with lactic acidosis and metformin is rarely known to produce this complication. No case of lactic acidosis has been reported with use of sulfonylureas (chlorpropamide and glipizide).