There are several classes of oral drugs for diabetes including

  • Sulfonylureas
  • Meglitinides
  • D-phenylalanine derivatives
  • Biguanides
  • Thiazolidinediones
  • Alpha-glucosidase inhibitors
  • Dipeptidyl peptidase-4 (DPP-4) inhibitors
  • Combination products

The classes of oral diabetes drugs work in different ways, so it's often helpful to take drugs from more than one class. For example, if a sulfonylurea stops working, you may be switched to metformin (Glucophage) or continued on the sulfonylurea in combination with metformin, an alpha-glucosidase inhibitor, or a thiazolidinedione.

Adding insulin is usually a last resort, but many new studies show that starting insulin early in the course of type 2 diabetes provides better glucose control, protects beta-cell function, and helps to prevent diabetes complications. That's why many experts now recommend early treatment with a combination of an oral drug plus insulin.

In October 2011, the U.S. Food and Drug Administration (FDA) approved a combination medication (called Juvisync) to treat type 2 diabetes and high cholesterol in adults. Juvisync combines a dipeptidyl peptidase 4 (DPP-4) inhibitor (sitagliptin) and a statin drug (simvastatin) and is available in three dosages.

Although statins may increase blood sugar levels in patients with type 2 diabetes, it is thought that this risk is small when compared to the risk for heart disease in these patients.

Publication Review By: the Editorial Staff at

Published: 20 Apr 2009

Last Modified: 08 Oct 2015