Regular insulin is short-acting human insulin used for prandial control and intravenous insulin therapy.

It has a slower onset and longer duration than rapid-acting insulin analogs.

→ Insulin Therapy

Regular insulin binds to the insulin receptor (tyrosine kinase receptor).

This activates:

• IRS signaling pathways
• PI3K/Akt cascade
• GLUT4 translocation in muscle and adipose tissue

Physiologic effects:

Liver:

• ↓ Gluconeogenesis
• ↑ Glycogen synthesis

Muscle:

• ↑ Glucose uptake
• ↑ Glycogen storage

Adipose:

• ↑ Glucose uptake
• ↓ Lipolysis

Regular insulin forms hexamers in solution.

These must dissociate before absorption, which slows onset.

Onset:

• 30–60 minutes

Peak:

• 2–4 hours

Duration:

• 6–8 hours

Compared to:

• Lispro
• Aspart

Regular insulin has:

• Slower onset
• Longer duration
• Greater risk of late hypoglycemia

Subcutaneous use:

• Mealtime insulin (must be given 30 minutes before eating)

Intravenous use:

• Diabetic Ketoacidosis (DKA)
• Hyperosmolar Hyperglycemic State (HHS)
• Critical care glucose control
• Severe hyperkalemia (drives potassium intracellularly)

Regular insulin is the insulin used for IV infusion.

Insulin deficiency leads to:

• Unchecked lipolysis
• Ketone production
• Metabolic acidosis

Treatment:

• IV Regular Insulin
• Fluid resuscitation
• Potassium monitoring

• Hypoglycemia
• Weight gain
• Hypokalemia (IV use)

Delayed hypoglycemia risk is higher compared to rapid analogs due to longer duration.

Rapid-acting analogs:

• Lispro
• Aspart
• Glulisine

Advantages of analogs:

• Faster onset
• Shorter duration
• Less stacking
• Reduced delayed hypoglycemia

Regular insulin advantages:

• IV use
• Lower cost
• Established inpatient role

• Only insulin used IV
• Slower onset than rapid analogs
• Must give 30 minutes before meals
• Used in DKA and HHS
• Can cause hypokalemia during IV therapy

• Insulin Therapy
• Lispro
• Aspart
• Diabetes Pharmacology