Glucosidase inhibitor (Precose) for the treatment of type 2 diabetes mellitus with a mechanism of action of delaying absorption of carbohydrates from the intestine.

50% of patients have adverse gastrointestinal side effects.

Decreasing postprandial glucose levels with acarbose, a alpha-glucosidase inhibitor, shown to decrease risk of myocardial infarction among individuals with glucose intolerance (Chiasson JL).

In the Study to Prevent Non-Insulin Dependent Diabetes Mellitus (STOP-NIDDM), a 3.3 year study of acarbose use was associated with a 25% relative risk reduction in the risk of diabetes.

An anti-diabetic drug used to treat diabetes mellitus type 2 and, prediabetes.

Sold as Precose.

Use in the U.S. is limited because it is not potent enough to justify the side effects of diarrhea and flatulence.

Pregnancy category US: B (No risk in non-human studies)

Oral agent.

Bioavailability extremely low.

Metabolism in the gastrointestinal tract.

Biological half-life 2 hours.

Excretion by kidney less than 2%.


A starch blocker, and inhibits alpha glucosidase, an intestinal enzyme that releases glucose from larger carbohydrates.

Inhibits enzymes needed to digest carbohydrates, specifically, alpha-glucosidase enzymes in the brush border of the small intestines, and pancreatic alpha-amylase. 

It is an inhibitor of alpha glycosidase that is approved for treatment of diabetes mellitus. 

It inhibits the upper GI enzymes alpha-glucosidases, which convert carbohydrates into monosaccharides. 

It reduce the symptoms of late dumping syndrome by interfering with carbohydrate absorption and thus decreasing the time delay between hyperglycemia and insulin response. 

Pancreatic alpha-amylase hydrolyzes complex starches to oligosaccharides in the lumen of the small intestine, whereas the membrane-bound intestinal alpha-glucosidases hydrolyze oligosaccharides, trisaccharides, and disaccharides to glucose and other monosaccharides in the small intestine.

Inhibition of these enzyme systems reduces the rate of digestion of complex carbohydrates.

As a result less glucose is absorbed because the carbohydrates are not broken down into glucose molecules.

It decreases blood glucose levels, and reduces HbA1c level long-term, with an absolute decrease of 0.7%, which is a decrease of about 10% in typical HbA1c values.

The drug should be administered at the start of main meals.

The amount of complex carbohydrates in the meal determines the effectiveness by decreasing postprandial hyperglycemia.

Adults may take doses of 25 mg 3 times daily, increasing to 100 mg 3 times a day.

Acarbose in doses of 100 mg to 200 mg significantly blunts the postprandial rise in glucose, insulin, and triglycerides.

The drug prevents the degradation of complex carbohydrates into glucose, so that some carbohydrate will remain in the intestine and be delivered to the colon.

Bacteria digest the complex carbohydrates that remain in the colon, causing gastrointestinal side-effects such as flatulence (78%) and diarrhea (14%).

Acarbose use may be limited by the occurrence of diarrhea secondary to fermentation of unabsorbed carbohydrates, as manifested by increased breath-hydrogen excretion and symptoms such as flatulence. 

Side effects are dose-related.

It is advisable to start with a low dose and gradually increase the dose.

Gastrointestinal side effects decreased significantly from 50% to 15% over 24 weeks.

If a patient experiences hypoglycemia, the patient must ingest something containing monosaccharides, such as glucose tablets.

It blocks the breakdown of table sugar and other complex sugars, so that fruit juice or starchy foods will not effectively reverse a hypoglycemic episode in a patient taking this drug.

Hepatitis has been reported, but clears when the medicine is stopped.

Liver enzymes should be checked before and during use of this medicine.

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