What is the protocol for initiating rapid-acting insulin (Regular insulin) therapy?

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Last updated: May 1, 2025View editorial policy

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From the Guidelines

To start rapid-acting insulin, the recommended initial dose is 4 U per meal, 0.1 U/kg per meal, or 10% of the basal insulin dose per meal if the HbA1c level is less than 8%. When initiating rapid-acting insulin therapy, it is essential to consider the patient's current basal insulin dose and HbA1c level 1. The rapid-acting insulin analogues are preferred due to their quick onset of action.

Key Considerations

  • The starting dose of mealtime insulin should be adjusted based on the patient's HbA1c level and basal insulin dose.
  • Providers should consider decreasing the basal insulin dose by the same amount as the starting mealtime dose to avoid hypoglycemia.
  • Rapid-acting insulin should be injected 15 minutes before meals or immediately after eating, and the injection site should be rotated to prevent tissue damage.
  • Patients should be educated on how to check their blood sugar regularly, recognize hypoglycemia symptoms, and have fast-acting glucose available to treat low blood sugar.

Important Factors

  • The action of rapid-acting insulin typically peaks within 1-2 hours and lasts 3-5 hours, closely mimicking the body's natural insulin response to eating.
  • The choice of rapid-acting insulin analogue, such as Humalog (insulin lispro), NovoLog (insulin aspart), or Apidra (insulin glulisine), should be based on the patient's specific needs and medical history 1.

From the FDA Drug Label

Insulins lower blood glucose by stimulating peripheral glucose uptake by skeletal muscle and fat, and by inhibiting hepatic glucose production. In a study in patients with type 1 diabetes (n=20), the glucose-lowering profiles of APIDRA and regular human insulin were assessed at various times in relation to a standard meal at a dose of 0. 15 units/kg The maximum blood glucose excursion (ΔGLUmax; baseline subtracted glucose concentration) for APIDRA injected 2 minutes before a meal was 65 mg/dL APIDRA given 2 minutes (APIDRA - pre) before the start of a meal compared to regular human insulin given 30 minutes (Regular - 30 min) before start of the meal

To start rapid acting insulin, such as APIDRA (glulisine), the following steps can be considered:

  • Dosing: Administer 0.15 units/kg subcutaneously, as studied in patients with type 1 diabetes.
  • Timing: Inject 2 minutes before a meal, as this has been shown to have a glucose-lowering effect similar to regular human insulin injected 30 minutes before a meal 2.
  • Key considerations:
    • The maximum blood glucose excursion for APIDRA injected 2 minutes before a meal was 65 mg/dL.
    • APIDRA has a faster onset of action and a shorter duration of activity than regular human insulin when given subcutaneously.

From the Research

Starting Rapid Acting Insulin

To start rapid acting insulin, the following steps can be considered:

  • Consult a healthcare professional to determine the appropriate type and dosage of rapid acting insulin for individual needs 3, 4.
  • Choose a rapid acting insulin analogue, such as insulin aspart, insulin lispro, or insulin glulisine, which have similar pharmacokinetic and pharmacodynamic characteristics and clinical efficacy/safety profiles 3, 4.
  • Consider the timing of insulin administration in relation to meals to limit mealtime glucose excursions 3.
  • Monitor blood glucose levels regularly to adjust insulin dosage and prevent hypoglycemia 5, 6.

Types of Rapid Acting Insulin

Some common types of rapid acting insulin include:

  • Insulin aspart (NovoLog) 3, 4, 5, 6
  • Insulin lispro (Humalog) 3, 4, 7
  • Insulin glulisine (Apidra) 4, 5, 6, 7

Considerations for Starting Rapid Acting Insulin

When starting rapid acting insulin, consider the following:

  • The risk of hypoglycemia and the need for regular blood glucose monitoring 3, 4, 5, 6
  • The potential for insulin regimen complexity and the need for patient education 3, 4
  • The importance of balancing improved glycemic control with the risk of hypoglycemia 3, 4

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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