Diabetes Medications – Oral

Oral medications are often prescribe for people with diabetes to control their blood sugar (glucose) levels. These "diabetes pills" may be prescribed for those with type 2 diabetes or gestational diabetes along with meal planning and physical activity .

Several kinds of diabetes pills are available. Each works in a different way. Some diabetes medicines work well together and may be used in combination.

Some people may need to take 2 or 3 kinds of these medications to get their blood sugar levels under control. Combination pills are also available for convenience that contain two kinds of diabetes medicine in one tablet.

Some people with type 2 diabetes may also take insulin with their diabetes pills. (There are presently no oral medications that provide glucose control for those with type 1 diabetes.)

Types of Diabetes Medications

Oral Medications - Pills

Most oral diabetes medications (pills) are categorized into six classes that work in different ways to lower blood glucose levels. These categories are:

  • Sulfonylureas
  • Biguanides
  • Alpha-glucosidase inhibitors
  • Meglitinides
  • Thiazolidinediones
  • DPP-4 inhibitors

Your doctor may ask you to start with one medication. If it doesn't help you reach your blood sugar targets, you may be asked to:

  • take more of the same pill
  • add another kind of pill
  • change to another type of pill
  • start taking insulin
  • start taking another injected medicine

Everyone is different. What works best for you depends on your usual daily routine, eating habits, and activities, and your other health conditions.


Sulfonylureas stimulate the beta cells of the pancreas to release more insulin. There have been several generations of medications with evolving benefits. These drugs are generally taken 1-2 times a day, before meals. All sulfonylurea drugs have similar effects on blood glucose levels, but they differ in side effects, how often they are taken, and interactions with other drugs.

Sulfonylureas include:

  • Amaryl® (glimepiride). This is a 2nd generation drug.
  • DiaBeta®, Glynase® PresTab, Micronase® (glyburide). This is a 2nd generation drug.
  • Diabinese® (chlorpropamide).
  • Dymelor® (acetohexamide)
  • Glucotrol®, Glucotrol® XL (glipizide). This is a 2nd generation drug.
  • Orinase® (tolbutamide)
  • Tolinase® (tolazamide)

Biguanides (Metformin)

The American Diabetes Association recommends metformin (Glucophage, Glucophage XR) as the first choice of diabetes medicine for most people with type 2 diabetes. Metformin can be taken alone or with other diabetes medicines.

Biguanides lower blood glucose levels primarily by decreasing the amount of glucose produced by the liver. Metformin also helps to lower blood glucose levels by making muscle tissue more sensitive to insulin so glucose can be absorbed. It is usually taken two times a day. A side effect of metformin may be diarrhea, but this is improved when the drug is taken with food.  

Biguanides include:

  • Glucophage® (metformin)
  • Glucophage® XR (extended-release metformin hydrochloride)

Alpha-glucosidase inhibitors

These drugs help the body to lower blood glucose levels by blocking the breakdown of starches, such as bread, potatoes, and pasta in the intestine. They also slow the breakdown of some sugars, such as table sugar. Their action slows the rise in blood glucose levels after a meal. They should be taken with the first bite of a meal. These drugs may have side effects, including gas and diarrhea.

Alpha-glucosidase inhibitors include:

  • Glyset® (miglitol)
  • Precose® (acarbose)


These drugs help insulin work better in the muscle and fat and also reduce glucose production in the liver. These drugs are effective at reducing A1C and generally have few side effects. The first drug in this group, troglitazone (Rezulin), was removed from the market because it caused serious liver problems in a small number of people. So far rosiglitazone and pioglitazone have not shown the same problems, but users are still monitored closely for liver problems as a precaution. Both drugs appear to increase the risk for heart failure in some individuals, and there is evidence that rosiglitazone may contribute to an increased risk for heart attacks.

Thiazolidinediones help insulin work better in the muscle and fat and also reduce glucose production in the liver. Thiazolidinediones include:

  • Actos® (pioglitazone)
  • Avandia® (rosiglitazone)


Meglitinides are drugs that also stimulate the beta cells to release insulin. They are taken before each of three meals. Because meglitinides stimulate the release of insulin, it is possible to have hypoglycemia (low blood glucose levels) following their use.

Ask your doctor if you are concerned about any of these side effects. Meglitinides include:

  • Prandin® (repaglinide)
  • Starlix® (nateglinide)

DPP-4 inhibitors

A new class of medications called DPP-4 inhibitors help improve hemoglobin A1C results without causing hypoglycemia. They work by by preventing the breakdown of a naturally occuring compound in the body, GLP-1. GLP-1 reduces blood glucose levels in the body, but is broken down very quickly so it does not work well when injected as a drug itself. By interfering in the process that breaks down GLP-1, DPP-4 inhibitors allow it to remain active in the body longer, lowering blood glucose levels only when they are elevated.

DPP-4 inhibitors do not tend to cause weight gain and tend to have a neutral or positive effect on cholesterol levels. DPP-4 inhibitors include:

  • Januvia® (sitagliptin)
  • Onglyza® (saxagliptin)
  • Tradjenta® (linagliptin)

Combination oral medicines

Combination oral medicines put together different kinds of pills. They include:

  • Glucovance® (glyburide and metformin hydrochloride)

Diabetes pills and insulin

Your doctor might ask you to take insulin and one of these diabetes pills:

  • A sulfonylurea
  • Metformin
  • Pioglitazone

How do I know if my diabetes medicines are working?

Learn to test your blood glucose levels. Ask your doctor or diabetes teacher about the best testing tools for you and how often to test. After you test your blood glucose, write down your blood glucose test results. Then ask your doctor or diabetes teacher if your diabetes medicines are working. A good blood glucose reading before meals is between 70 and 140 mg/dL.

Ask your doctor or diabetes teacher about how low or how high your blood glucose should get before you take action. For many people, blood glucose is too low below 70 mg/dL and too high above 240 mg/dL.

One other number to know is the result of a blood test your doctor does called the hemoglobin A1C. It shows your blood glucose control during the past 2 to 3 months. For most people, the target for hemoglobin A1C is less than 7 percent.

Reference: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

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This information is for general educational uses only. It may not apply to you and your personal medical needs. This information should not be used in place of a visit, call, consultation with or the advice of your physician or health care professional.

Communicate promptly with your physician or other health care professional with any health-related questions or concerns.

Be sure to follow specific instructions given to you by your physician or health care professional.

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