USMLE

Metformin

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Anti-Diabetic Drugs
  1. Insulin Overview
  2. Rapid Acting Insulin
  3. Short Acting Insulin
  4. Intermediate Acting Insulin
  5. Long Acting Insulin
  6. Metformin
  7. Sulfonylureas
  8. Canagliflozin
  9. Pioglitazone

Summary

Metformin is a drug that works to improve insulin sensitivity in the body. In this way, metformin lowers blood sugar and treats hyperglycemia associated with type 2 diabetes. Metformin is actually the preferred treatment in type 2 diabetics because it does NOT cause hypoglycemia like insulin does. Side effects of metformin include lactic acidosis, which is especially common if the patient also receives IV contrast dye. Another side effect of metformin is gastrointestinal upset, manifesting as nausea and vomiting.

Key Points

  • Metformin (Glucophage)
    • Mechanism
      • Improves insulin sensitivity
      • Increases peripheral glucose uptake and use
      • Decreases hepatic production and intestinal absorption of glucose
    • Clinical Use
      • Hyperglycemia in Type II Diabetes Mellitus
        • Prevents blood sugar spikes after meals
        • First choice medication for Type II diabetes
        • Preferred over insulin because it does not cause hypoglycemia
      • Polycystic ovary syndrome (PCOS)
        • Off-label use
    • Side Effects and Adverse Reactions
      • Lactic acidosis
        • Rare, but lethal and if the following signs and symptoms are noticed, the provider should be notified:
          • Hyperventilation (fast, shallow breathing)
          • Drowsiness
          • Muscle pain
          • Fatigue, chills
        • Increased risk when taken with IV contrast
          • Discontinue prior to IV contrast iodine exposure (CT scan, cardiac catheterization) and resume 48 hours after
        • Increased risk when taken with alcohol
        • Avoid in patients with liver or kidney disease
      • Gastrointestinal disturbances
        • Nausea, vomiting
        • Metallic taste in mouth
      • Malabsorption of amino acids, B12, and folic acid