Are Novolog (insulin aspart) and Lispro (insulin lispro) the same?

Novolog and Humalog Are Not the Same, but Have Similar Clinical Profiles

No, Novolog (insulin aspart) and Humalog (insulin lispro) are not the same insulin products, though they belong to the same class of rapid-acting insulin analogs with very similar pharmacokinetic and pharmacodynamic profiles.

Key Differences and Similarities

• Chemical Structure: Novolog (insulin aspart) and Humalog (insulin lispro) are different insulin molecules with distinct amino acid modifications:

  • Insulin aspart (Novolog) has a substitution of proline with aspartic acid 1
  • Insulin lispro (Humalog) has a reversal of proline and lysine positions in the C-terminal portion of the B chain 2

• Pharmacokinetic Profile: Both have nearly identical action profiles:

  • Onset of action: 0.25-0.5 hours for both insulins 1
  • Peak action: 1-3 hours for both insulins 1
  • Duration of action: 3-5 hours for both insulins 1

• Clinical Use: Both are used in the same clinical scenarios:

  • As prandial (mealtime) insulin in basal-bolus regimens 1
  • In continuous subcutaneous insulin infusion (insulin pumps) 1
  • For management of both type 1 and type 2 diabetes 1

Clinical Implications

• Interchangeability: While they have similar profiles, they are not considered interchangeable products and require a prescription change to switch between them 1

• Efficacy: Clinical studies show comparable glycemic control between the two insulins:

  • Both provide better postprandial glycemic control than regular human insulin 3, 4
  • Both have similar effects on HbA1c reduction when used in comparable regimens 5

• Hypoglycemia Risk: Both have similar risk profiles for hypoglycemia:

  • Lower risk of hypoglycemia compared to regular human insulin 4
  • Similar safety profiles between the two analogs 5

Practical Considerations

• Timing of Administration: Both can be administered immediately before meals, unlike regular human insulin which requires injection 30 minutes before meals 2, 4

• Insulin Pumps: Both are suitable for use in insulin pumps with similar stability profiles 1

• Cost and Access: Pricing may differ between the products, which could affect patient access and adherence 1

Subtle Differences

• Some studies suggest insulin glulisine may have a slightly faster onset of action compared to insulin lispro or insulin aspart, but this has not translated into demonstrable clinical benefits 5

• In one comparative study, biphasic insulin aspart 30 showed improved postprandial glycemic control compared to biphasic insulin lispro 25, but this refers to premixed formulations rather than the rapid-acting components alone 6

Conclusion

While Novolog (insulin aspart) and Humalog (insulin lispro) are different insulin molecules, their clinical profiles are so similar that the choice between them is often based on factors such as formulary availability, cost, and patient/provider preference rather than significant clinical differences in efficacy or safety.