Pharmacology.
Acarbose is an oral alpha-glucosidase inhibitor indicated for the management of hyperglycemia caused by type 2 diabetes mellitus. Inhibition of this gut enzyme system effectively reduces the rate of complex carbohydrate digestion and the subsequent absorption of glucose, thereby lowering postprandial glucose excursions in type 2 diabetes. In obese and non-obese patients with type 2 diabetes, acarbose monotherapy is associated with a 0.5-1% decrease in hemoglobin A1c.
Administration and Adult Dosage.
PO for type 2 diabetes (as monotherapy or with a sulfonylurea) 25 mg, tid initially, just before meals. Increase to 50 mg tid after 4-8 weeks and, if necessary, to 100 mg tid after 4-8 additional weeks.
Dosages >100 mg tid are not recommended because of increased risk of hepatotoxicity, and patients weighing ≤60 kg should not receive >50 mg tid.
Safety and efficacy not established in Pediatric age group.
Dosage Forms.
Tab 25, 50, 100 mg.
Patient Instructions.
Take acarbose at the beginning of each meal. When a meal is skipped, also skip taking this medication. If a dose is missed, do not take it unless it is just before the next meal. If hypoglycemia occurs, dextrose (glucose) needs to be ingested; sucrose (table sugar) is not effective.
Pharmacokinetics.
Fate. The drug is poorly absorbed from the GI tract (<2%). It undergoes extensive metabolism in the GI tract via intestinal flora and digestive enzymes. The clinical effect is not dependent on the serum level achieved. All absorbed acarbose and metabolites are renally excreted. In patients with renal impairment, plasma acarbose concentrations are elevated in relation to the degree of renal dysfunction.
t1⁄2.
About 2 hr with normal renal function.
Adverse Reactions.
The major side effects of acarbose are flatulence, diarrhea, and abdominal pain. Acarbose monotherapy is not associated with hypoglycemia; however, patients managed with combination therapy (with a sulfonylurea or insulin) can experience hypoglycemia secondary to the other drug. In this setting, manage hypoglycemia with oral glucose (if the patient is conscious) or IV glucose or glucagon (if the patient is unconscious) rather than with a complex carbohydrate (eg, sucrose). Attempting to manage hypoglycemia with oral sugar sources other than glucose is not effective in acarbose-treated patients and might have grave consequences.
Contraindications.
Inflammatory bowel disease; colonic ulceration; obstructive bowel disorders; cirrhosis; type 1 diabetes; history of diabetic ketoacidosis.
Precautions.
Use with caution in patients with disorders of digestion or absorption or with medical conditions that might deteriorate with increased intestinal gas formation. Not recommended in patients with Cr >2 mg/dL.
Drug Interactions.
Charcoal and other intestinal adsorbents as well as digestive preparations containing amylase, pancreatin, and related enzymes should not be taken concurrently with acarbose.
Parameters to Monitor.
Monitor clinical symptoms of hyperglycemia (mainly polyphagia, polyuria, polydipsia, or numbing or tingling of feet) or hypoglycemia (hunger, nervousness, sweating, palpitations, headaches, confusion, drowsiness, anxiety, or blurred vision) when taken concurrently with insulin or insulin secretagogues (eg, sulfonylureas). Self-monitoring of fasting and selected postprandial blood glucose levels by the patient is also helpful. Long-term diabetic control may best be monitored using hemoglobin Alc.
