Linagliptin is an inhibitor of DPP-4, an enzyme that degrades the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). By inhibiting DPP-4 Linagliptin increases the concentrations of active incretin hormones and stimulates the release of Insulin in a glucose dependent manner and decreases the level of Glucagon in the circulation and thus regulates the glucose homeostasis. Incretin hormones are secreted at a low basal level throughout the day and levels rise immediately after meal intake. GLP-1 and GIP increase Insulin biosynthesis and secretion from pancreatic beta-cells in the presence of elevated blood glucose levels. Furthermore, GLP-1 also reduces Glucagon secretion from pancreatic alpha-cells, resulting in a reduction in hepatic glucose output.
The recommended dose of Linagliptin is 5 mg once daily and can be taken with or without food. If added with Metformin, the dose of Metformin should be maintained and Linagliptin administered concomitantly. When used in combination with Sulfonylurea, a lower dose of Sulfonylurea may be considered to reduce the risk of hypoglycemia.