What is the calculation for Humalog (insulin lispro) dosing for meal coverage?

Humalog Meal Coverage Dosing Calculation

For meal coverage with Humalog (insulin lispro), start with 4 units per meal, or calculate 10% of the basal insulin dose, or use 0.1 units/kg body weight, and administer 0-2 minutes before eating. 1

Initial Dosing Strategies

The American Diabetes Association provides three evidence-based approaches for initiating prandial Humalog:

• Fixed dose approach: Start with 4 units before each meal 1
• Percentage-based approach: Use 10% of the current basal insulin dose for each meal 1
• Weight-based approach: Calculate 0.1 units/kg body weight per meal 1

Begin with one meal first (typically the largest meal or the meal with greatest postprandial glucose excursion) rather than adding prandial insulin to all three meals simultaneously 1

Carbohydrate-Based Calculation

For patients proficient in carbohydrate counting:

• Use approximately 1 unit of Humalog per 10-15 grams of carbohydrate consumed 1
• This ratio should be individualized based on insulin sensitivity and glucose monitoring results 1
• Patients receiving enteral bolus feedings should receive approximately 1 unit per 10-15 grams of carbohydrate before each feeding 1

Titration Algorithm

Increase the prandial dose by 1-2 units (or 10-15% of the current dose) every 3 days based on postprandial glucose readings 1

Target postprandial glucose goals:

• Measure glucose 1-2 hours after meals 1
• Adjust doses based on pattern management rather than single readings 1

For hypoglycemia without clear cause:

• Reduce the corresponding meal dose by 10-20% 1

Timing Considerations

Administer Humalog 0-2 minutes before the meal for optimal postprandial glucose control 2

• Humalog has onset of action within 5 minutes 3, 4
• Peak action occurs at 1-2 hours 3, 4
• Duration of action is 3-4 hours 3, 4
• This rapid pharmacokinetic profile allows for immediate pre-meal dosing, unlike regular human insulin which requires 20-45 minute pre-meal administration 5

Basal Insulin Adjustment

When adding prandial insulin to an existing basal regimen:

• If A1C is <8% when starting prandial insulin, reduce basal dose by 4 units or 10% to prevent hypoglycemia 1
• With significant additions to prandial doses (particularly at dinner), consider decreasing basal insulin 1
• Monitor for "overbasalization" signals: elevated bedtime-to-morning differential, postprandial-to-preprandial differential, or increased hypoglycemia 1

Special Populations

Hospital/Enteral Feeding

• For continuous tube feedings: calculate total daily nutritional insulin as 1 unit per 10-15 grams carbohydrate per day, or 50-70% of total daily insulin dose 1
• Add correctional insulin every 4 hours using rapid-acting insulin like Humalog 1

Older Adults

• Use simplified sliding scale while adjusting prandial insulin 1, 4
• Do not use rapid-acting insulin at bedtime in older adults 1, 4
• For premeal glucose >250 mg/dL, give 2 units supplemental Humalog 1
• For premeal glucose >350 mg/dL, give 4 units supplemental Humalog 1

Common Pitfalls to Avoid

• Avoid starting prandial insulin at all three meals simultaneously - this increases complexity and hypoglycemia risk; start with one meal first 1
• Do not continue aggressive basal insulin titration when adding prandial coverage - this leads to overbasalization and increased hypoglycemia 1
• Avoid using Humalog at bedtime - its rapid onset and short duration make it inappropriate for overnight coverage 1, 4
• Do not mix Humalog with insulin glargine due to pH incompatibility, though it can be mixed with NPH insulin 4
• Recognize that Humalog's rapid onset can cause quick hypoglycemia if dosed excessively 3