25.13 : Oral Hypoglycemic Agents: α-Glucosidase Inhibitors

α-glucosidase inhibitors, including acarbose (Precose), miglitol (Glyset), and voglibose (Voglib) (primarily available in Asia), are drugs that control blood sugar levels by delaying the digestion of starch and disaccharides. They achieve this by inhibiting α-glucosidase enzymes in the intestine, which slow the absorption of carbohydrates in the intestine, which in turn leads to a prolonged release of the glucoregulatory hormone GLP-1 from intestinal L-cells.

Acarbose and miglitol are typically administered in 25-, 50-, or 100-mg tablets before meals, with doses adjusted based on glucose levels and gastrointestinal symptoms. Acarbose has minimal absorption, while miglitol, resembling glucose, is absorbed at a 50%-100% rate. Both drugs are cleared by the kidney. These inhibitors can cause malabsorption, flatulence, diarrhea, and abdominal bloating. Rarely, acarbose can lead to mild to moderate elevations of hepatic transaminases. Hypoglycemia may occur when combined with insulin or an insulin secretagogue. They can also interfere with the absorption of medications like digoxin, propranolol, and ranitidine. They are not recommended for patients with stage 4 renal failure.

Despite potential adverse effects, these inhibitors can be beneficial adjuncts to diet and exercise for type 2 diabetic patients struggling to reach glycemic targets. They can be combined with other oral antidiabetic agents or insulin without causing weight gain or significant effects on plasma lipids. However, their prescription in the U.S. is limited due to modest glucose-lowering benefits and gastrointestinal side effects.