Acarbose: Uses, Mechanism of Action, Dosage and Side Effects

It is used to treat type 2 diabetes.

It is a generic that is sold in Europe and China as Glucobay, in North America as Precose, and in Canada as Prandase.

A recent large study concludes that “acarbose is effective, safe, and well tolerated in a large cohort of Asian patients with type 2 diabetes.”

One possible explanation for the different opinions is an observation that acarbose is significantly more effective in patients consuming a relatively high carbohydrate oriental diet.

It is a starch blocker and inhibits alpha glucosidase, an intestinal enzyme that releases glucose from the largest carbohydrates. It is composed of an acarviosin residue with a maltose at the reducing end.

Mechanism of action of acarbose

Pancreatic alpha-amylase hydrolyzes complex starches to oligosaccharides in the lumen of the small intestine, while intestinal membrane-bound 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.

Less glucose is absorbed because carbohydrates do not break down into glucose molecules.

In diabetic patients, the short-term effect of these drug therapies is to lower current blood glucose levels; the long-term effect is a reduction in the HbA 1c level.

This reduction averages an absolute decrease of 0.7%, which is a decrease of approximately 10% in typical HbA 1c values ​​in diabetes studies.


Because acarbose prevents the digestion of complex carbohydrates, the drug should be taken at the beginning of main meals (taken with the first bite of food).

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

Side effects of acarbose

Since these effects are dose related, it is generally recommended to start with a low dose and gradually increase the dose to the desired amount.

One study found that gastrointestinal side effects decreased significantly (from 50% to 15%) over 24 weeks, even with constant dosing.

Hepatitis has been reported with the use of acarbose. It usually goes away when the medicine is stopped. Therefore, liver enzymes must be monitored before and during the use of this medicine.

Most common side effects

  • Stomach ache.
  • Diarrhea.
  • Flatulence.

These side effects generally develop within the first few weeks after taking acarbose. They should decrease as you continue taking the drug, usually within a few days to a couple of weeks. Talk to your doctor or pharmacist if they are more serious or if they don’t go away.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms seem life threatening or if you think you are having a medical emergency. Serious side effects and their symptoms may include the following:

Allergic skin reaction

Symptoms can include:

  • Eruption.
  • Redness.
  • Swelling of your skin
Liver problems

Symptoms can include:

  • Yellowing of the whites of your eyes or skin.
  • Swelling of the stomach
  • Pain in the upper right part of your stomach.
Pneumatosis cystoides intestinalis

These are gas-filled cysts in the wall of your intestines. They can cause intestinal problems, such as holes, blockage, or bleeding. Symptoms can include:

  • Diarrhea.
  • Mucus discharge
  • Rectal bleeding.
  • Constipation .