What are the recommendations for using short-acting insulins, such as Humalog (lispro), Novolog (aspart), and Apidra (glulisine), for mealtime glucose control in diabetes management?

Short-Acting Insulins for Mealtime Glucose Control in Diabetes Management

Short-acting insulin analogs (lispro, aspart, glulisine) should be administered within 15 minutes before meals or immediately after meals to optimally control postprandial glucose excursions in diabetes management. 1

Pharmacological Properties of Short-Acting Insulin Analogs

• Short-acting insulin analogs (Humalog/lispro, Novolog/aspart, Apidra/glulisine) have a more rapid onset of action (5 minutes) and shorter duration of action (3-4 hours) compared to regular human insulin 2, 3
• These insulins are designed to mimic the normal physiological insulin surge that occurs after meals, providing better postprandial glucose control 3, 4
• The rapid onset allows for more flexible meal timing compared to regular human insulin, which requires injection 30 minutes before meals 4, 5

Dosing Recommendations

• Initial dosing for mealtime insulin is typically 4 units per meal or 0.1 units/kg per meal 2
• Total daily insulin requirements generally range between 0.5-1.0 units/kg/day, with approximately 50% given as mealtime boluses and 50% as basal insulin 1
• Dose adjustments should be based on blood glucose monitoring, with consideration for:
  • Carbohydrate content of meals
  • Pre-meal blood glucose levels
  • Anticipated physical activity 6, 2

Administration Guidelines

• Short-acting insulin analogs should be given within 15 minutes before a meal or immediately after a meal 1
• These insulins should generally be used in regimens with an intermediate or long-acting insulin 1
• Injection sites include the abdominal wall, thigh, upper arm, or buttocks, with rotation within the same region to reduce lipodystrophy risk 1
• For patients using insulin pumps, the reservoir should be changed at least every 7 days, and infusion sets and insertion sites should be changed every 3 days 1

Meal Planning and Insulin Matching

• Patients using short-acting insulins should learn carbohydrate counting or another meal planning approach to match insulin doses to carbohydrate intake 6
• For patients on multiple daily injections or insulin pumps:
  • Take mealtime insulin before eating
  • Meals can be consumed at different times
  • Insulin doses may need adjustment if physical activity is performed within 1-2 hours of injection 6

Mixing Insulin Considerations

• Insulin glargine should not be mixed with other forms of insulin due to its low pH 6
• Rapid-acting insulins can be mixed with NPH, lente, and ultralente insulins 6
• When rapid-acting insulin is mixed with intermediate or long-acting insulin, the mixture should be injected within 15 minutes before a meal 6
• Commercially available pre-mixed insulins may be used if the insulin ratio is appropriate to the patient's requirements 6

Hypoglycemia Management

• The risk of hypoglycemia is a common concern with all insulin therapy 1
• Treatment of hypoglycemia should include 15-20g of glucose (glucose tablets or carbohydrate-containing foods/beverages) 6
• When blood glucose levels are around 50-60 mg/dL, treatment with 15g of glucose can be expected to raise blood glucose levels by approximately 50 mg/dL 6
• If hypoglycemia persists after 15-20 minutes, the treatment should be repeated 6

Common Pitfalls and Considerations

• Patients must understand the rapid onset of action of short-acting analogs to avoid unexpected hypoglycemia 2
• Dose adjustments may be needed during stress, major illness, or with changes in exercise, meal patterns, or coadministered drugs 1
• For patients transitioning from regular human insulin to rapid-acting analogs, a slightly greater basal insulin supply may be needed due to the shorter duration of action of the analogs 3
• Patients should not skip meals when using short-acting insulins to reduce hypoglycemia risk 6
• Always carry a source of quick-acting carbohydrates to treat potential hypoglycemia, especially when physical activity is performed 6