ABSTRACT
Since its discovery, insulin has been the mainstay of treatment for patients with type 1 diabetes. For patients with type 2 diabetes, we have traditionally relied on the oral agents, and these pharmaceutical agents have served us well. With the various drug classes now available, the oral agents address the pathophysiological abnormalities recognized to be present in the patient with type 2 diabetes. Specifically, oral hypoglycemic agents such as the sulfonylureas depend on insulin production by β cells and can markedly increase meal secretion of insulin. The biguanides, i.e., metformin, and the more recently introduced thiazolidinediones improve glycemic control by decreasing hepatic glucose production and sensitizing the peripheral tissues to insulin. Nevertheless, the mode of action for these two classes of drugs also depends on adequate endogenous insulin production or on exogenous insulin. In addition, the results of long-term prospective studies have demonstrated that the natural history of type 2 diabetes suggests a progressive disease in which multiple therapies may be required to achieve glycemic control. In this regard, the combination of drugs from the various classes has shown additive benefits to improve diabetic control, and combination oral therapy
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may be considered a routine approach in the management of type 2 diabetes. However, with the progressive nature of the disease, and the failure of combination oral therapy to adequately control the patient, insulin has emerged as a more viable treatment option much earlier in the disease process in patients with type 2 diabetes.
