Alpha-Glucosidase Inhibitors for Diabetes

Medically Reviewed by Nayana Ambardekar, MD on May 08, 2021

Alpha-glucosidase inhibitors are pills that treat type 2 diabetes. There are two medications in this group, or class, of drugs: acarbose (Precose) and miglitol (Glyset). They help keep the amount of glucose in your blood from going up too fast after you eat.

Your doctor might prescribe an alpha-glucosidase inhibitor if you've recently been diagnosed with type 2 and your blood sugar tends to shoot up after a meal. If you're already taking diabetes medications and you still have high blood sugars, your doctor might want you to take an alpha-glucosidase inhibitor, too.

How They Work

These drugs block the breakdown of starchy foods such as bread, potatoes, and pasta, and they slow down the absorption of of some sugars, such as table sugar. You take an alpha-glucosidase inhibitor with the first bite of each meal. Most people take a pill three times a day.

An alpha-glucosidase inhibitor will usually lower your A1c (the "average" of your blood sugar control over a few months) by about 0.5% to 0.8%.

Side Effects

If you're also taking other diabetes medications or insulin, check with your doctor about how likely you are to have low blood sugars. If you're only taking an alpha-glucosidase inhibitor, you probably won't have low blood sugars.

Your doctor might start you off with a low dose and then raise it a little bit at a time to help avoid trouble in your gut, such as:

These side effects will usually go away in a few weeks. Call your doctor if they don't.

Who Shouldn't Take Them

Alpha-glucosidase inhibitors aren't good if you have:

You shouldn't take acarbose if you have:

These drugs aren't recommended for pregnant women.

WebMD Medical Reference



American Diabetes Association: "What Are My Options?"

Archives of Medical Science: "α-Glucosidase Inhibitors and Their Use in Clinical Practice."

Johns Hopkins Guide to Diabetes: "Alpha Glucosidase Inhibitors."

Joslin Diabetes Center: "Oral Diabetes Medications Summary Chart," "Guideline for Detection and Management of Diabetes in Pregnancy."

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