In contrast to sulfonylureas, Acarbose does not enhance insulin secretion. The antihyperglycemic action of acarbose results from a competitive, reversible inhibition of pancreatic alpha-amylase and membrane-bound intestinal alpha-glucoside hydrolase enzymes. Pancreatic alpha-amylase hydrolyzes complex starches to oligosaccharides in the lumen of the small intestine, while the membrane-bound intestinal alpha-glucosidase hydrolyzes oligosaccharides, trisaccharides, and disaccharides to glucose and other monosaccharides in the brush border of the small intestine. In diabetic patients, this enzyme inhibition results in delayed glucose absorption and a lowering of postprandial hyperglycemia. Because its mechanism of action is different, the effect of Acarbose to enhance glycemic control is additive to that of sulfonylureas, insulin or metformin when used in combination. In addition, Acarbose diminishes the insulinotropic and weight-increasing effects of sulfonylureas. Acarbose has no inhibitory activity against lactase and consequently would not be expected to induce lactose intolerance.

Acarbose is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus.

The recommended starting dosage of Acarbose is 25 mg given orally three times daily at the start (with the first bite) of each main meal. However, some patients may benefit from more gradual dose titration to minimize gastrointestinal side effects. This may be achieved by initiating treatment at 25 mg once per day and subsequently increasing the frequency of administration to achieve 25 mg t.i.d. Maintenance Dosage Once a 25 mg t.i.d. dosage regimen is reached, dosage of Acarbose should be adjusted at 4–8 week intervals based on one-hour postprandial glucose or glycosylated hemoglobin levels, and on tolerance. The dosage can be increased from 25 mg t.i.d. to 50 mg t.i.d. Some patients may benefit from further increasing the dosage to 100 mg t.i.d. The maintenance dose ranges from 50 mg t.i.d. to 100 mg t.i.d.

Acarbose is contraindicated in patients with known hypersensitivity to the drug. Precose is contraindicated in patients with diabetic ketoacidosis or cirrhosis. Acarbose is also contraindicated in patients with inflammatory bowel disease, colonic ulceration, partial intestinal obstruction or in patients predisposed to intestinal obstruction. In addition, Acarbose is contraindicated in patients who have chronic intestinal diseases associated with marked disorders of digestion or absorption and in patients who have conditions that may deteriorate as a result of increased gas formation in the intestine.

Diarrhea, gas, upset stomach, constipation, or stomach pain may occur in the first few weeks of treatment as your body adjusts to this medication but usually improve with time. Follow your prescribed diet to help lessen these side effects. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Overdose Effects

Unlike sulfonylureas or insulin, an overdose of Acarbose will not result in hypoglycemia. An overdose may result in transient increases in flatulence, diarrhea, and abdominal discomfort which shortly subside. In cases of overdosage the patient should not be given drinks or meals containing carbohydrates (polysaccharides, oligosaccharides and disaccharides) for the next 4–6 hours.

Pregnancy & Lactation

Pregnancy Category B. The safety of Acarbose in pregnant women has not been established. A small amount of radioactivity has been found in the milk of lactating rats after administration of radiolabeled acarbose. It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, Acarbose should not be administered to a nursing woman.

Precautions & Warnings

Because of its mechanism of action, Acarbose when administered alone should not cause hypoglycemia in the fasted or postprandial state. Sulfonylurea agents or insulin may cause hypoglycemia. Because Acarbose given in combination with a sulfonylurea or insulin will cause a further lowering of blood glucose, it may increase the potential for hypoglycemia. Hypoglycemia does not occur in patients receiving metformin alone under usual circumstances of use, and no increased incidence of hypoglycemia was observed in patients when Acarbose was added to metformin therapy.

Oral glucose (dextrose), whose absorption is not inhibited by Acarbose, should be used instead of sucrose (cane sugar) in the treatment of mild to moderate hypoglycemia. Sucrose, whose hydrolysis to glucose and fructose is inhibited by Acarbose, is unsuitable for the rapid correction of hypoglycemia. Severe hypoglycemia may require the use of either intravenous glucose infusion or glucagon injection.