[Incretin enhancer: sitagliptin].

Recently, incretin-based therapies have become available for patients with type 2 diabetes in Japan. Sitagliptin is one of several DPP-4 inhibitors. After an OGTT, active endogenous GLP-1 concentrations are increased about twofold by sitagliptin. In clinical trials, sitagliptin was shown to be effective in monotherapy and in combination with other oral agents. Hypoglycemic events were not increased in monotherapy. However in Japan, severe hypoglycemic events have been reported especially in older patients with high dose of sulfonylurea. The long-term effectiveness needs to be evaluated in Japanese patients with type 2 diabetes.