What is the protocol for a preprandial (before meal) insulin sliding scale?

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Last updated: May 30, 2025View editorial policy

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From the Guidelines

A preprandial insulin sliding scale should be implemented based on the most recent guidelines, which recommend giving 2 units of short- or rapid-acting insulin for premeal glucose >250 mg/dL and 4 units for premeal glucose >350 mg/dL, as stated in the 2025 standards of care in diabetes 1.

Key Considerations

  • The sliding scale should be individualized based on the patient's insulin sensitivity, weight, and overall diabetes control.
  • Rapid-acting insulins like lispro (Humalog), aspart (NovoLog), or glulisine (Apidra) should be used for this purpose, administered 15 minutes before meals.
  • The goal is to maintain premeal glucose levels between 90-150 mg/dL, with adjustments made every 2 weeks based on finger-stick glucose testing performed before lunch and before dinner.
  • If 50% of premeal finger-stick values over 2 weeks are above goal, the dose should be increased or another agent added, and if >2 premeal finger-stick values/week are <90 mg/dL, the dose of medication should be decreased.

Implementation

  • Start with a basic scale and adjust as needed based on patient response and glucose monitoring data.
  • Regular monitoring and adjustment are essential, as insulin needs may change with activity levels, illness, or other factors.
  • The sliding scale should complement, not replace, a basal insulin regimen for most patients with diabetes.
  • Patients should record their blood glucose readings and insulin doses to help identify patterns requiring adjustment of the scale, as recommended in the 2025 standards of care in diabetes 1.

From the Research

Preprandial Insulin Sliding Scale

  • The concept of a preprandial insulin sliding scale is not directly addressed in the provided studies, but the studies do discuss the use of rapid-acting insulin analogs such as insulin aspart, lispro, and glulisine in the management of diabetes 2, 3, 4, 5, 6.
  • Insulin aspart and lispro have been compared in several studies, with results indicating that they have similar efficacy and safety in controlling postprandial glucose excursions in patients with type 1 diabetes 2, 4, 5.
  • A study comparing insulin glulisine to insulin aspart in children with type 1 diabetes found that insulin aspart was more effective in controlling 2- and 4-hour postprandial blood glucose excursions 3.
  • Another study compared the efficacy and safety of insulin glulisine, lispro, and aspart in patients with type 1 diabetes using continuous subcutaneous insulin infusion, and found that glulisine had comparable glucose control to lispro and aspart 6.
  • A systematic review of randomized controlled trials comparing aspart and lispro in type 1 and type 2 diabetes found that both treatments had comparable efficacy and safety, with similar decreases in glycated hemoglobin and similar dosing and weight changes 5.

Key Findings

  • Insulin aspart and lispro have similar efficacy and safety in controlling postprandial glucose excursions in patients with type 1 diabetes 2, 4, 5.
  • Insulin glulisine has comparable glucose control to lispro and aspart in patients with type 1 diabetes using continuous subcutaneous insulin infusion 6.
  • The choice of rapid-acting insulin analog may depend on individual patient factors, such as age, diabetes duration, and insulin regimen 3, 6.

Insulin Regimens

  • The studies discussed the use of rapid-acting insulin analogs in various insulin regimens, including multiple daily injections and continuous subcutaneous insulin infusion 2, 3, 4, 5, 6.
  • The use of a preprandial insulin sliding scale may be considered in conjunction with these regimens to optimize glucose control 2, 3, 4, 5, 6.

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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