Two extrapancreatic effects shown to be important in the action of glipizide are an increase in insulin sensitivity and decrease in hepatic glucose production. For patients whose daily insulin requirement is greater than 20 units, the insulin dose should be reduced by 50 and GLUCOTROL XL therapy may begin at usual dosages. In addition, in elderly, debilitated or malnourished patients, and patients with impaired renal or hepatic function, the initial and maintenance dosing should be conservative to avoid hypoglycemic reactions. Laboratory Tests The pattern of laboratory test abnormalities observed with GLUCOTROL was similar to that for other sulfonylureas. In glipizide tablett ametlik veebisait humans GLUCOTROL appears to lower the blood glucose acutely by stimulating the release of insulin from the pancreas, an effect dependent upon functioning beta cells in the pancreatic islets. Some patients, especially those taking higher doses, may be directed to take this drug twice day.