Brand Name - Precose

  • Type of Drug: Antidiabetic.
  • Prescribed for: Non-insulin-dependent diabetes.

General Information

Acarbose works against diabetes in a way different from all other antidiabetes medicines. It interferes with enzymes in the intestine responsible for breaking the complex carbohydrates found in starchy foods down into simple sugars, including glucose, and lowers blood sugar by delaying the absorption of glucose into the blood. Because it works by a different method than the sulfonylurea-type oral antidiabetes drugs and Metformin, the blood-sugar-lowering effect of Acarbose is additive to that of other antidiabetes drugs.

Acarbose may also be used by people who are unable to control their blood sugar by diet alone. Half of each dose of Acarbose remains unchanged in the intestines and passes out of the body in the stool; about 2 percent is absorbed into the blood, and the rest is broken down in the intestines. Most of Acarbose’s side effects are directly related to the fact that it leaves undigested carbohydrates in the lower intestines. In studies of Acarbose, both black and white patients responded similarly, but a better response was seen in Hispanic patients.

Cautions and Warnings

Acarbose should not be used if you are allergic or sensitive to it. People should not use Acarbose if they have diabetic ketoacidosis, cirrhosis, severe kidney disease, inflammatory bowel disease, ulcers of the colon, intestinal obstruction, severe digestive disease, or absorption diseases, or if intestinal gas will be a severe problem. Acarbose may lead to liver inflammation.
Possible Side Effects

  • Most common: stomach gas (in 3/4 of people who take it), abdominal pains, and diarrhea. These side effects tend to improve or go away after a few weeks.
  • Other: liver irritation and some minor abnormalities in blood tests.

Drug Interactions

  • Acarbose adds to the blood-sugar-lowering effect of sulfonylureas and other antidiabetes drugs.
  • Like other antidiabetes agents, the effects of Acarbose will be countered by drugs that raise blood sugar, including diuretics, thyroid hormones, corticosteroids, Phenothiazines, Estrogens, oral contraceptives, Phenytoin, Nicotinic Acid, stimulants (and decongestants), calcium channel blockers, and Isoniazid.
  • Activated charcoal, antacids, and other drugs intended to absorb stomach contents, and digestive enzyme preparations may reduce the effectiveness of Acarbose. Separate these drugs from Acarbose by at least 2 hours.

Food Interactions

Acarbose must be taken at the beginning (with the first bite) of each meal.

Usual Dose

Adult: 25 to 50 mg 3 times a day. Maximum dose is 100 mg 3 times a day in people weighing 132 pounds or more.
Child: not recommended.


There is no experience with Acarbose overdosage, but diarrhea, abdominal pains, and intestinal gas can be expected. Excess blood-sugar lowering should not occur. Call your local poison center for more information.

Special Information

It is essential to take each dose of Acarbose at the beginning of each meal. Since the drug works in the intestines, it has to be there at the same time as the food you are digesting.
As with all antidiabetes medicines, people taking Acarbose must follow their doctor’s instructions for diet and exercise. Read product labels carefully or check with your pharmacist before buying any nonprescription medicine to be sure it is safe for diabetics to take with Acarbose.
If you forget a dose of Acarbose, skip it and continue with your regular schedule. Taking a missed dose later on will not provide any benefit.

Special Populations

Animal studies of Acarbose showed no effects on the developing fetus. There is no information available on the effect of Acarbose in pregnant women. As with all medicines, Acarbose should be taken during pregnancy only if absolutely necessary and only if the potential risks have been completely discussed with your doctor. It is not known if Acarbose passes into breast milk. Nursing mothers who must take this medicine should consider bottle-feeding their babies.

Blood levels of Acarbose are higher in older adults, but this is not considered important. Older adults with severe kidney disease should avoid this medicine.