What is the difference between NovoLog (insulin aspart) and Lispro insulin (insulin lispro)?

Difference Between NovoLog (Insulin Aspart) and Lispro (Humalog) Insulin

NovoLog (insulin aspart) and Humalog (insulin lispro) are both rapid-acting insulin analogs with very similar pharmacokinetic profiles, onset of action, and duration, with only minor clinical differences between them that rarely affect treatment decisions.

Key Similarities

• Pharmacokinetic Profile:

  • Both are rapid-acting insulin analogs with:
    • Onset of action: 15-30 minutes
    • Peak action: 1-3 hours
    • Duration of action: 3-5 hours 1
  • Both are designed for mealtime insulin coverage
  • Both can be administered immediately before meals (unlike regular human insulin which requires 30-45 minute pre-meal dosing) 1, 2

• Clinical Applications:

  • Both are used in basal-bolus insulin regimens for type 1 and type 2 diabetes
  • Both are suitable for insulin pump therapy (CSII) 1
  • Both have similar efficacy in glycemic control when used appropriately
  • Both have similar safety profiles with comparable rates of hypoglycemia 3

Minor Differences

1. Chemical Structure:

   • Insulin aspart (NovoLog): B28 position has aspartic acid substituted for proline
   • Insulin lispro (Humalog): B28 and B29 positions are reversed (lysine and proline)

2. Absorption Rate:

   • Some studies suggest insulin aspart may have slightly more rapid absorption:
     • One study found higher peak insulin concentrations with aspart (24.6 mU/L vs 20.8 mU/L for lispro) 4
     • Aspart showed slightly lower glucose concentrations at 50 minutes post-injection in one study 4

3. Formulations and Mixtures:

   • Lispro has NPL (neutral protamine lispro) mixtures (25/75 and 50/50 formulations) 2
   • Aspart has different premixed formulations with protamine-based intermediate-acting insulin

4. Manufacturing and Brand:

   • NovoLog is manufactured by Novo Nordisk
   • Humalog is manufactured by Eli Lilly

Clinical Decision Making

When choosing between these insulins:

1. Consider formulary/cost factors:

   • Insurance coverage often dictates which insulin is more accessible
   • Median AWP costs are similar but can vary by formulation 5

2. Patient-specific factors:

   • Prior experience with either insulin
   • Individual response patterns (rare cases of differential response)
   • Compatibility with specific insulin delivery devices

3. Practical considerations:

   • Both insulins can be used interchangeably in most clinical scenarios with minimal dose adjustments
   • Switching between these insulins typically requires minimal to no dose adjustment

Common Pitfalls to Avoid

• Dosing errors: Both are rapid-acting insulins and should not be confused with long-acting insulins 1
• Timing of administration: Both should be given immediately before meals, not 30 minutes prior like regular human insulin 1, 2
• Incomplete coverage: Neither should be used as monotherapy without basal insulin coverage in type 1 diabetes 1
• Pump compatibility: Ensure compatibility with specific insulin pump models when used for CSII therapy

In most clinical scenarios, the choice between NovoLog and Humalog can be based on non-pharmacological factors such as cost, insurance coverage, and patient preference, as their clinical profiles are remarkably similar.