Alpha-Glucosidase Inhibitors for Type 2 Diabetes

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Alpha-Glucosidase Inhibitors for Type 2 Diabetes


Generic NameBrand Name

How It Works

Acarbose and miglitol help keep blood sugar levels within a target range by slowing the rate at which the intestines absorb sugar (glucose) from food. These medicines do not cause the pancreas to produce more insulin. They will not cause low blood sugar (hypoglycemia) unless they are used in combination with other oral medicines for diabetes or with insulin.

Why It Is Used

Alpha-glucosidase inhibitors have proved helpful for people with type 2 diabetes who have not been able to keep their blood sugar levels within a safe range by eating a balanced diet, losing weight, and exercising. They are very helpful in controlling the blood sugar levels of people who have high blood sugar levels right after they eat.

These medicines are most useful for people who have just been diagnosed with type 2 diabetes and who have blood sugar levels only slightly above the level for diabetes. They may also be used to treat people who are taking other medicine for diabetes, such as metformin.1

Both medicines may be used alone, with another medicine for diabetes, or with insulin.

How Well It Works

These medicines have been found to be especially helpful for people who tend to have high blood sugar levels right after they eat (post-prandial hyperglycemia).

People taking insulin who start using acarbose usually are able to decrease the amount of insulin they take.

People taking acarbose alone tend not to gain weight or may lose a small amount of weight.

Side Effects

The most common side effects are temporary digestive symptoms: typically belly discomfort, excessive gas (flatulence), and diarrhea. You may be able to reduce this side effect by decreasing the amount of high-carbohydrate foods you eat, such as pasta, breads, and rice.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

These medicines do not cause low blood sugar or weight gain, which are common side effects of the sulfonylurea medicines and insulin.

Acarbose and miglitol may need to be taken 3 times a day, with each meal.

If you take one of these medicines along with another medicine that lowers blood sugar (such as insulin or a sulfonylurea medicine), your blood sugar level can drop very low. If your blood sugar level does drop too low, use glucose tablets—rather than other simple sugars such as fructose, lactose, or sucrose—to raise your blood sugar level. If you do not treat low blood sugar with glucose tablets, it may require more food to raise your blood sugar level than it would for a person who is not taking one of these medicines.


Few studies have been done on the use of oral medicines for type 2 diabetes in children. And these medicines have not been approved by the Therapeutic Products Directorate (TPD) for use in children. But because these oral medicines are safe for adults, most doctors use them to treat children who have type 2 diabetes. Also, these medicines are not absorbed into the bloodstream, so they do not have systemic side effects.

But the increase in belly gas associated with their use makes them less desirable than other oral medicines for diabetes.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.



  1. American Diabetes Association (2009). Medical management of hyperglycemia in type 2 diabetes: A consensus algorithm for the initiation and adjustment of therapy. Diabetes Care, 32: 193–203.


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Matthew I. Kim, MD - Endocrinology
Last Revised August 4, 2010

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.