Oral Diabetes Medications

Alpha-glucosidase Inhibitors

The drugs acarbose (Precose) and miglitol (Glyset) block the action of the alpha-glucosidase enzymes that break down carbohydrates (starches and sucrose) in your digestive tract. As a result, digestion is delayed, glucose passes into the bloodstream more slowly, and blood glucose levels stay lower after a meal.

On the negative side, the undigested carbohydrates often cause gas, diarrhea, and abdominal discomfort. Although these side effects tend to lessen over time, Precose and Glyset are not recommended for people with inflammatory bowel disease, liver or kidney disease, or other serious intestinal disorders.

When taken alone, Precose and Glyset do not cause hypoglycemia. However, hypoglycemia may occur when either drug is used in combination with a sulfonylurea, a meglitinide, or insulin. It is important to remember that alpha-glucosidase inhibitors block the digestion of sucrose, so don't reach for a candy bar if you develop hypoglycemia. You need to eat glucose (dextrose) or drink milk or fruit juice (fruit contains fructose and glucose).

Publication Review By: Written by: Christopher D. Saudek, M.D.; Simeon Margolis, M.D., Ph.D.

Published: 21 Apr 2009

Last Modified: 10 Mar 2015