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Pharmacology of Diabetes Medications

Introduction to Diabetes Medications

  • Insulin is a crucial hormone for controlling blood sugar (glycemia) post-meal, produced in the pancreas.
  • Produced by beta cells in the islets of Langerhans.

Types of Diabetes

Type 1 Diabetes Mellitus

  • Arises when beta cells in the pancreas fail to produce sufficient insulin.
  • Typically affects younger individuals and is an autoimmune condition.
  • Leads to little or no insulin production.

Type 2 Diabetes Mellitus

  • The body produces insulin but the tissues are resistant to it.
  • Primarily affects adults; increasing cases in children due to obesity.

Gestational Diabetes

  • Develops during pregnancy, causing high blood sugar.
  • Governed by risk factors like obesity and family history of diabetes.

Type 1.5 Diabetes (LADA)

  • A slower-developing form of autoimmune diabetes occurring in adults.
  • Features of both Type 1 and Type 2 diabetes.

Classes of Diabetes Medications

  1. Hypoglycemics (Oral Antidiabetics)

    • Insulin Secretagogues: Stimulate insulin release from pancreatic beta cells.
    • Non-Sulfonylurea Secretagogues: Includes biguanides and thiazolidinediones.

  2. Biguanides

    • Metformin is the main drug in this class.
    • Mechanisms of Action:
      • Reduces hepatic glucose production by activating AMPK.
      • Increases insulin sensitivity.
      • Decreases intestinal absorption of glucose.
    • Adverse Effects: Gastrointestinal issues, potential for Vitamin B12 deficiency.
    • Contraindications: Renal issues, history of alcoholism.

  3. Thiazolidinediones (TZDs)

    • Improve insulin sensitivity and decrease glucose production in the liver.
    • Main drugs: Rosiglitazone and Pioglitazone.
    • Adverse Effects: Edema, weight gain, and potential liver impairment.

  4. Sulfonylureas

    • Stimulate insulin secretion from beta cells by closing ATP-sensitive potassium channels.
    • Examples include Glimepiride and Glyburide.
    • Best for older patients with a shorter diabetes duration.
    • Adverse Effects: Risk of hypoglycemia.

  5. Alpha-Glucosidase Inhibitors

    • Slow carbohydrate digestion in the intestine, leading to slower glucose absorption.
    • Adverse Effects: Gastrointestinal issues.

Insulin Therapy

  • Insulin is essential for those who cannot produce enough.

  • Types of Insulin:

    • Rapid-Acting Insulins: Start acting within 5-15 mins, peak at 1 hour.
    • Short-Acting Insulins: Start in 30 mins, peak at 2-3 hours.
    • Intermediate-Acting Insulins: Start within 1-2 hours, peak at 4-12 hours.
    • Long-Acting Insulins: No peak effect, but lasts longer (up to 24 hours).

  • Administration: Subcutaneously, primarily in the abdominal region.

Dosage Considerations in Pregnancy

  • Insulin remains the standard for controlling blood glucose in pregnant women.
  • Dosing can be based on weight or a combination of weight and gestational age.

Conclusion

  • Diabetes management involves understanding the specific type of diabetes and tailored medication to ensure blood glucose levels remain stable. The therapeutic approach integrates lifestyle changes with pharmacological interventions.