Insulin

Insulin is a hormone that regulates blood sugar by enabling glucose uptake into cells, used in diabetes management.

Introduction:

• It is a peptide hormone produced by beta cells in the pancreas.
• It regulates blood glucose levels by facilitating glucose uptake into cells (liver, fat, and muscle tissues) and aids in the metabolism of carbohydrates, fats, and proteins.
• In diabetes, impaired insulin production or function necessitates external administration.

Types of Insulin

1. Rapid-Acting (Onset: ~15 min, Peak: 1-2 hrs, Duration: 3-5 hrs)
   • Examples: Lispro, Aspart, Glulisine
   • Uses: Mealtime glucose control.
2. Short-Acting (Onset: ~30 min, Peak: 2-3 hrs, Duration: 5-8 hrs)
   • Examples: Regular Insulin (Humulin R, Novolin R)
   • Uses: Pre-meal and basal needs.
3. Intermediate-Acting (Onset: ~2-4 hrs, Peak: 4-12 hrs, Duration: 12-18 hrs)
   • Examples: NPH Insulin (Humulin N, Novolin N)
   • Uses: Basal coverage.
4. Long-Acting (Onset: ~1-2 hrs, Peak: Minimal, Duration: ~24 hrs)
   • Examples: Glargine, Detemir, Degludec
   • Uses: Basal insulin, once/twice daily.
5. Ultra-Long-Acting (Onset: ~30-90 min, Peak: None, Duration: >24 hrs)
   • Examples: Degludec
   • Uses: Extended basal needs.

Mechanism of Action

Insulin lowers blood glucose by:

• Facilitating Glucose Uptake: Promotes entry of glucose into muscle and fat cells.
• Inhibiting Gluconeogenesis: Reduces glucose production in the liver.
• Promoting Glycogen Synthesis: Enhances storage of glucose as glycogen in the liver and muscles.
• Stimulating Lipogenesis: Encourages fat storage and inhibits lipolysis.

Uses

• Type I Diabetes Mellitus: Essential for survival due to absolute insulin deficiency.
• Type II Diabetes Mellitus: Used when oral antidiabetics are insufficient to control blood glucose levels.
• Gestational Diabetes: Manages elevated blood sugar levels during pregnancy.
• Hyperkalemia: Insulin shifts potassium into cells, lowering blood potassium levels.

Side Effects

• Hypoglycemia: Low blood sugar levels, presenting as dizziness, sweating, confusion, and in severe cases, loss of consciousness.
• Weight Gain: Increased fat storage due to insulin’s anabolic effects.
• Injection Site Reactions: Redness, swelling, or itching at the injection site.
• Allergic Reactions: Rare but may include rash or anaphylaxis.
• Lipodystrophy: Changes in fat tissue at injection sites from repeated use.

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