Medication Update


South Med J. 2002;95(1) 

In This Article

Alpha-Glucosidase Inhibitors

Mode of Action

The alpha-glucosidase inhibitors are competitive, reversible inhibitors of alpha-amylase from the pancreas and alpha-glucosidase, which is found in the brush border of the small intestine. This inhibition results in reduced postprandial increases in blood glucose levels by delaying the digestion of dietary carbohydrates.


Known hypersensitivity to the particular alpha-glucosidase inhibitors, or components of their formulations. Significant renal dysfunction, as evidenced by a serum creatinine >2mg/dL. Cirrhosis. Diabetic ketoacidosis. Inflammatory bowel disease, intestinal obstruction or predisposition to obstruction, colon ulceration, or other disorders of digestion or absorption. Pregnancy Category: B.

Adverse Effects

Gastrointestinal effects, including abdominal pain (11.7%-21%), diarrhea (28.7%-33%), and flatulence (41.5%-77%), are very common. They may be reduced by slow titration of the dose, and generally improve as treatment is continued.

Drug-Drug Interactions

May reduce serum digoxin concentrations. Digestive enzymes and intestinal adsorbents, such as charcoal, should not be taken at the same time as the alpha-glucosidase inhibitors, as they will decrease the efficacy of the alpha-glucosidase inhibitors. Miglitol decreases the bioavailability of propranolol and ranitidine.

Drug-Food Interactions

The COX-2 inhibitors, especially in higher doses, should generally be taken with meals to reduce GI upset.

Recommended Doses

Acarbose (precose): Starting dose, 25 mg TID, usual dose range, 50-100 mg TID. Should be taken with the first bite of each meal.

Miglitol (glyset): Starting dose, 25 mg TID, usual dose range, 50-100 mg TID. Should be taken with the first bite of each meal.

Dosage Forms Available

Acarbose: 50 mg and 100 mg tablets.

Miglitol: 25 mg, 50 mg, and 100 mg tablets.


Acarbose: Bayer.

Miglitol: Bayer.

Other Points of Interest

While use of the alpha-glucosidase inhibitors alone is not associated with hypoglycemia, if they are used in combination with other antidiabetic medications, hypoglycemia may occur. This should be treated by administering oral dextrose. Sucrose (table sugar or candy bars) will not reverse the hypoglycemia due to the pharmacologic effects of the alpha-glucosidase inhibitors.



  1. Hutchison TA, Shahan DR, Anderson ML (eds): DRUGDEX System. MICROMEDEX, Inc, Englewood, Colo. (Edition expires 12/2000)

  2. Hebel SK, Katstrup EK (eds): Drug Facts and Comparisons. St. Louis, Mo. 2001



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