Type 2 Oral Diabetes Medications (Oral)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

Early Signs and Symptoms of Type 2 Diabetes

Early signs and symptoms of type 2 diabetes may include

  • increased urination,
  • weight loss,
  • fatigue,
  • nausea,
  • vomiting, and
  • vaginal infections.

What are oral diabetes medications?

Oral diabetes are medications used to improve blood sugar (glucose) control in patients with type 2 diabetes.

What are the types of oral diabetes medications?

Currently, there are nine drug classes of oral diabetes medications approved for the treatment of type 2 diabetes.

  1. α-glucosidase inhibitors
  2. Biguanides
  3. Sulfonylureas
  4. Meglitinides
  5. Thiazolidinediones
  6. DPP-4 inhibitors
  7. Sodium-glucose cotransporter (SGLT)-2 inhibitors
  8. Dopamine agonists
  9. Bile acid sequestrants

These medications differ in the way they function in the body to reduce blood glucose.


Metformin (Glucophage) is the only biguanide available in the United States and is generally the first choice for oral treatment of type 2 diabetes mellitus. Metformin improves

  • the body's response to natural insulin,
  • decreases the absorption of glucose from the intestines, and
  • reduces the production of glucose by the liver.


Sulfonylureas are the oldest classes of oral diabetes medications. Sulfonylureas work primarily by stimulating the release of insulin. Insulin is the hormone responsible for regulating blood glucose by increasing the uptake of blood glucose by tissues and increasing storage of glucose in the liver.


Meglitinides and sulfonylureas have a similar mechanism of action. Meglitinides are short acting glucose lowering medications. They stimulate the secretion of insulin from the pancreas.


Thiazolidinediones enhance insulin sensitivity meaning that the effect of a given amount of insulin is greater. Thiazolidinediones also are referred to as peroxisome proliferator-activated receptor ? or PPAR-? agonists.

α-glucosidase inhibitors

α-glucosidase inhibitors delay the digestion and absorption of starch or carbohydrates by inhibiting enzymes in the small intestine which help breakdown these molecules. The starches and carbohydrates are broken down into glucose, which then is absorbed from the intestine and increases the level in the blood.

DPP-4 inhibitors

DPP-4 inhibitors help lower blood glucose by increasing the production of insulin from the pancreas and reducing the release of glucose from the liver.

SGLT2 inhibitors

SGLT2 inhibitors or sodium-glucose cotransporter 2 inhibitors are the newest class of oral diabetes medications. They work by reducing absorption of glucose from the fluid that is filtered from blood by the kidney, causing more glucose to be eliminated in the urine. These medications increase urinary glucose excretion and consequently lower blood sugar levels.

Bile acid sequestrants

Currently the only bile acid sequestrant approved for the oral treatment of type 2 diabetes is colesevelam (Welchol). Bile acid sequestrants function primarily in the intestines where they bind to and decrease the reabsorption of bile acid. The exact mechanism by which these agents lower blood glucose is not known.

Dopamine agonists

Bromocriptine (Cycloset) is a dopamine agonist approved for the treatment of type 2 diabetes. The exact mechanism whereby bromocriptine lowers blood glucose is not known.

Medically Reviewed by a Doctor on 10/8/2015

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