Medicine & USMLE

Alpha-Glucosidase Inhibitors

Diabetes Drugs (New)
  1. DPP-4 Inhibitors
  2. GLP-1 Analogs
  3. Insulin Overview
  4. Insulin Preparations
  5. Metformin (Biguanides)
  6. TZDs (Thiazolidinediones)
  7. Sulfonylureas
  8. Meglitinides
  9. SGLT2 Inhibitors
  10. Alpha-Glucosidase Inhibitors
  11. Pramlintide (Amylin Analogs)


Alpha-glucosidase inhibitors are a class of drugs that includes acarbose and miglitol. These drugs lower blood sugar in the treatment of type 2 diabetes mellitus. As their name suggests, these drugs inhibit the action of alpha-glucosidase enzymes, which decreases carbohydrate hydrolysis in food as it passes through the gut tract. This primarily happens at the intestinal brush border to inhibit glucose absorption, which lowers blood glucose levels. Since glucose absorption from food is decreased, these drugs also lead to decreased postprandial hyperglycemia. Patients with decreased kidney function may experience higher drug levels in blood and therefore develop side effects, which is why these drugs should be used with caution in patients with renal insufficiency. Notably, these drugs typically do not cause hypoglycemia, and usually have no effect on weight. The most common side effects to look out for are diarrhea and flatulence.

Key Points

  • Alpha (α)-glucosidase inhibitors
    • Drug Names
      • Acarbose
      • Miglitol
    • Mechanism
      • Inhibit alpha (α)-glucosidases at intestinal brush-border
        • Decreased carbohydrate hydrolysis (breakdown)
          • Prevents breakdown of disaccharides into simple sugars that can be absorbed by the intestines
        • Decreased intestinal absorption of glucose
          • Decreased postprandial hyperglycemia
    • Clinical Use
      • Treats diabetes mellitus
        • Typically used with refractory type 2 diabetes mellitus
    • Side Effects
      • Flatulence and Diarrhea
        • Flatulence, bloating, diarrhea caused by the fermentation of unabsorbed carbohydrates
      • Use with Caution in Renal Insufficiency (not recommended)
        • Especially with Miglitol, since miglitol is absorbed systemically and excreted unchanged in the urine. Poor kidney function can therefore lead to increased doses and side effects
        • Acarbose is metabolized nearly completely within the gastrointestinal tract, so very little is excreted in the urine.
      • Weight neutral
        • No effect on weight
      • Does not cause hypoglycemia
        • Since this drug does not cause insulin release, the risk of hypoglycemia is low when used in isolation
        • This drug may slightly increase the risk of hypoglycemia when it is taken together with insulin or insulin-releasing drugs