Classes of Oral Diabetes Medications – And How They Work

Oral diabetes medications are not initially needed for every patient with diabetes mellitus type 2. Many people find they can control their type 2 diabetes by controlling their diet, getting more exercise and maintaining a healthy weight.

"But over time, most people with type 2 diabetes will need to take a medicine, too. Many also have heart disease, high blood pressure, and/or elevated cholesterol, and will need to take medicines for these conditions along with a diabetes drug. "(1)

Oral diabetes medications are useful tools that can help a person with diabetes better manage blood sugar levels along with a good diet and exercise plan.

One common misconception is that oral diabetes drugs are insulin or insulin therapy. Insulin, however, cannot be taken orally because the enzymes of your digestive track would destroy it. Oral medications work to control blood sugar levels but are not insulin.

Classes of oral diabetes medications

There are six distinct classes of oral diabetes medications which include:

  • Alpha-glucosidase inhibitors, this class uses the drug names acarbose (Precose) and miglitol (Glyset). It works by slowing down the digestion of certain carbohydrates in the intestines and is taken with the first bite of food at a meal.
  • Biguanides use the drug name metformin (Glucophage, Glucophage XR, Riomet [liquid formulation]). It works by decreasing production of glucose by the liver and improving insulin sensitivity in the liver, muscles and fat cells. It is taken with food to lessen the side effects.
  • D-Phenylalanine derivatives use the drug name nateglinide (Starlix) and work by stimulating the pancreas to release more insulin. This class of oral diabetes medications is taken 1 to 30 minutes before a meal.
  • Meglitinides, which use the drug name repaglinide (Prandin) aids the diabetic by stimulating the pancreas to release more insulin. This medication is taken 15 minutes before a meal.
  • Sulfonylureas, is a class that uses the drug name chlorpropamide (Diabinese), glyburide (Diabeta, Glynase, Micronase), glipizide (Glucotrol), glipizide extended-release (Glucotrol XL), or glimepiride (Amaryl). It works by stimulating the pancreas to release more insulin and is taken with food or before a meal.
  • Thiazolidinediones, uses the drug name pioglitazone (Actos) or rosiglitozone (Avandia) and works by improving insulin sensitivity and decreasing production of glucose in the liver. It is taken with or between meals.
  • Combination products, go by the names Avandamet (rosiglitazone and metformin), Glucovance (glyburide and metformin) or Metaglip (glipizide and metformin). They work by combining the affects of the individual medications and can be taken as directed.

Each of the classes of oral diabetes medications has a different mechanism of action to help the diabetic patient control their blood glucose levels. A diabetic will usually begin by taking one oral diabetes medication along with making healthy lifestyle changes.

The results will be monitored and future treatment will be based on those results.

(1) Consumer Reports (2009). Treating type 2 diabetes: the oral diabetes drugs. Retrieved from

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