A pseudotetrasaccharide and inhibitor of alpha-glucosidase and pancreatic alpha-amylase with antihyperglycemic activity. Acarbose binds to and inhibits alpha-glucosidase, an enteric enzyme found in the brush border of the small intestines that hydrolyzes oligosaccharides and disaccharides into glucose and other monosaccharides. This prevents the breakdown of larger carbohydrates into glucose and decreases the rise in postprandial blood glucose levels. In addition, acarbose inhibits pancreatic alpha-amylase which hydrolyzes complex starches to oligosaccharides in the small intestines.