Alpha glucosidase inhibitors: Uses, common brands, and safety info

Most drugs commonly used to treat Type 2 diabetes, a condition in which there is too much sugar, or glucose, in the blood, either have a direct effect on improving insulin secretion or a direct effect on improving the use of insulin by the body’s cells. Even though these drugs are effective in controlling blood glucose levels between meals (also called fasting blood glucose levels) some may not be as effective controlling blood glucose levels immediately following a meal (known as postprandial blood glucose).  That’s when alpha glucosidase inhibitors can help.

Alpha glucosidase inhibitors (AGIs), also known as α-glucosidase inhibitors, are a type of drug that work differently in that they specifically target postprandial glucose levels by blocking glucose absorption into the bloodstream. AGIs are considered generally safe, effective, and relatively inexpensive. This table lists commonly used AGIs followed by information on how they work, what conditions they treat, safety, and cost.

Other alpha glucosidase inhibitor

Voglib (voglibose) is an AGI available in a number of countries worldwide but has not been approved for use in the U.S.

What are alpha glucosidase inhibitors?

Alpha glucosidase inhibitors (AGIs) are oral antidiabetic drugs commonly used in the treatment of people with Type 2 diabetes. AGIs reduce blood sugar levels after eating a meal by slowing the absorption of carbohydrates. They are particularly useful for people with Type 2 diabetes who are at greater risk of experiencing hypoglycemia, or low blood sugar levels, or who are not good candidates for other antidiabetic drugs such as sulfonylureas, GLP-1 agonists, SGLT2 inhibitors, or metformin. AGIs may be given alone or in combination with other antidiabetic drugs.

How do alpha glucosidase inhibitors work?

Foods high in carbohydrates, such as starchy or sugary foods, are broken down in the digestive system into glucose, a type of sugar that is easily absorbed into the bloodstream. The body uses glucose as fuel to provide energy. In people with diabetes, controlling the amount of glucose levels in the blood is very important because their blood glucose may rise above normal levels which may lead to health problems.

AGIs slow down the release of glucose into the bloodstream by blocking the enzymes in the small intestine that break down dietary carbohydrates into glucose. This enzyme inhibition results in delayed absorption of the sugar from foods, reducing the rise in blood glucose levels after eating, i.e., reducing the postprandial glucose levels.

What are alpha glucosidase inhibitors used for?

AGIs have been approved by the U.S. Food and Drug Administration (FDA)  for people with Type 2 diabetes mellitus, alone or in combination with other diabetic drugs, to improve glycemic control. Although AGIs have shown some benefits in people with Type 1 diabetes and in decreasing body weight, they are not FDA approved for these purposes. Some clinical trial data have suggested that AGIs reduce the risk of cardiovascular events associated with Type 2 diabetes, such as heart attacks, but longer-term studies have been called for.

Who can take alpha glucosidase inhibitors?

Adults

AGIs are approved as an adjunct to diet and exercise for adults with Type 2 diabetes who have poorly controlled blood glucose levels, particularly immediately following meals  (postprandial hyperglycemia).  They may be used as monotherapy or in combination with other antidiabetic drugs or insulin. AGIs are particularly effective in adults with Type 2 diabetes who have kidney or liver problems and are at a higher risk for developing lactic acidosis, a condition in which lactic acid builds up in the bloodstream. AGIs also do not cause hypoglycemia, or low blood sugar, making them a useful substitute to sulfonylureas, which are associated with hypoglycemic episodes.

Children

The efficacy and safety of AGIs have not been fully evaluated in randomized controlled trials of pediatric patients with Type 2 diabetes and their use is not recommended in children or adolescents.

Seniors

In clinical studies for both Precose and Glyset, there were no overall differences seen in the effectiveness and safety in older patients with Type 2 diabetes as compared to younger patients. The use of AGIs has remained somewhat unpopular with many elderly patients because of gastrointestinal side effects such as flatulence (passing gas), bloating, and diarrhea. 

Women who are pregnant or breastfeeding

There have been no adequate and well-controlled studies on the use of AGIs in pregnant women and they should not be administered unless the potential benefit justifies the potential risk to the fetus. It is not known whether AGIs are excreted in human milk therefore it is not recommended they be given to nursing women.

A woman’s healthcare provider is the best source of information when managing Type 2 diabetes care during pregnancy or while breastfeeding.

Are alpha glucosidase inhibitors safe?

Hepatitis

In rare instances, the use of Precose (acarbose) has been reported to be linked with acute hepatitis. Liver function tests may be recommended before starting therapy and during treatment with Precose.

Drug interactions

Digestive enzyme medications containing carbohydrate-splitting enzymes, such as amylase or pancreatin (taken when the pancreas does not release enough digestive enzymes into the gut to digest food), may reduce the effect of AGIs and should not be taken concomitantly.

Recalls

There are no current AGI product recalls as of January 2022. 

Restrictions

Persons with known hypersensitivity or allergies to the ingredients should not take AGIs. AGI therapy is contraindicated in Type 2 patients with any of the following conditions:

• Diabetic ketoacidosis

• Cirrhosis

• Inflammatory bowel disease

• Colonic ulcer

• Partial GI obstruction

• GI obstruction risk

• Malabsorption syndromes

Are alpha glucosidase inhibitors controlled substances?

No, AGIs are not controlled substances.

Common alpha glucosidase inhibitors side effects

Gastrointestinal (GI) disturbances are the most commonly reported side effects of AGIs. These result from the mechanism of action of the drugs which cause an increase in undigested carbohydrates in the colon leading to excess gas formation. Flatulence, or passing gas, is the most commonly reported side effect of AGIs. Diarrhea and abdominal pain due to bloating may also occur. GI symptoms tend to diminish over time and the severity may be reduced by starting with a lower dose. A diet high in carbohydrates may increase the GI adverse effects so it is important to discuss meal planning with a healthcare professional prior to starting therapy.

How much do alpha glucosidase inhibitors cost?

AGIs have a wide price range depending on the specific drug, quantity, and dosage. Almost all Medicare and insurance plans will cover AGIs. Both AGIs are available in generic formulations which are much less expensive than their brand-name counterparts. A SingleCare discount card could reduce prescription costs up to 80% at participating pharmacies.