USMLE

Insulin Overview

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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

Insulin is a hormone that lowers blood sugar, and is given as a drug in contexts of high blood sugar or hyperglycemia, such as that seen in diabetes. However, if too much insulin is given, the blood sugar levels can drop too low and cause hypoglycemia. Insulin is also given to lower potassium levels. One side effect of insulin is lipohypertrophy, or fat buildup, at the injection site. This can be prevented by rotating injection sites.

Key Points

  • Insulin Overview
    • Mechanism
      • Lowers blood glucose levels by stimulating cellular uptake of glucose by binding to insulin receptors and inhibiting hepatic glucose production
      • Promotes storage of glucose in the form of glycogen in the liver
    • Clinical Uses
      • Hyperglycemia
        • Type I and Type II Diabetics
        • Diabetic Ketoacidosis
          • Intense insulin deficit characterized by fruity breath and rapid deep respirations (Kussmaul respirations)
        • Pancreatitis
      • Hyperkalemia
        • Insulin increases potassium uptake into cells, reducing blood potassium levels
    • Administration
      • When a patient is sick with an infection, or has other body stressors, they may experience an increase in blood glucose levels, and therefore require additional insulin
      • Unopened bottles of insulin should be refrigerated. Insulin should be administered at room temperature, so plan to remove insulin from the refrigerator about 30 minutes before administering.
      • Opened bottles of insulin can be stored at room temperature for 4 weeks.
      • Before administering insulin, roll the vial between your palms. Do not shake the insulin vial.
    • Side Effects
      • Hypoglycemia
        • Shakiness
        • Chills
        • Sweating
        • Irritability
        • Tachycardia
        • Dizziness
        • Hunger
        • Seizures
        • Altered level of consciousness
      • Hypokalemia
        • Insulin shifts potassium into the cells, resulting in low potassium in the bloodstream
        • Often occurs at resolution of DKA, after administration of high doses of insulin
      • Lipohypertrophy
        • An accumulation of extra fat at the site of many subcutaneous insulin injections, creating a lump that changes drug absorption and dosing
        • Systematically rotate injection sites to avoid lipohypertrophy