General Starting Dose of Humalog
For adults with type 1 diabetes, start with a total daily insulin dose of 0.5 units/kg/day, dividing approximately 50% as basal insulin and 50% as Humalog (prandial insulin) distributed among three meals. 1, 2
Type 1 Diabetes Dosing
Initial Calculation:
- Calculate total daily dose (TDD) as 0.5 units/kg/day for metabolically stable patients 3, 1, 2
- Acceptable range is 0.4-1.0 units/kg/day depending on clinical context 1, 2
- Divide the prandial portion (50% of TDD) equally among three meals 3, 1
Example: For a 70 kg patient:
- TDD = 0.5 × 70 = 35 units/day
- Prandial insulin (Humalog) = 17.5 units/day total
- Distribute as approximately 6 units before each meal 3, 2
Special Populations Requiring Adjustment:
- Diabetic ketoacidosis: Higher than 0.5 units/kg/day required initially 1, 2
- Honeymoon phase/young children: Lower doses of 0.2-0.6 units/kg/day 1, 2
- Puberty: May require approaching 1.0 units/kg/day or higher 1, 2
- Pregnancy or acute illness: Higher doses needed 1, 2
Type 2 Diabetes Dosing
When Adding Prandial Insulin:
For patients with type 2 diabetes already on basal insulin who need prandial coverage, start with 4 units of Humalog before the largest meal OR use 10% of the current basal insulin dose. 3, 2
Titration Protocol:
- Increase by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings 3, 2
- Target postprandial glucose <180 mg/dL 2
- If hypoglycemia occurs, reduce dose by 10-20% immediately 3, 2
Critical Threshold: Add prandial insulin when basal insulin exceeds 0.5 units/kg/day without achieving glycemic targets, rather than continuing to escalate basal insulin alone 3, 2
Administration Timing
Humalog must be given 0-15 minutes before meals, not after eating. 3 This timing is critical because Humalog has an onset of action at 0.25-0.5 hours, peaks at 1-3 hours, and has a duration of 3-5 hours 4
Common Pitfalls to Avoid
- Never give Humalog at bedtime as this significantly increases nocturnal hypoglycemia risk 3, 2
- Never use sliding scale insulin as monotherapy - scheduled basal-bolus regimens are superior 3, 2
- Never continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia with prandial insulin 3, 2
- Do not delay prandial insulin addition when basal insulin approaches the 0.5 units/kg/day threshold without achieving targets 3, 2
Foundation Therapy
Continue metformin at maximum tolerated dose (up to 2000-2550 mg daily) when using insulin therapy in type 2 diabetes, as this combination provides superior glycemic control with reduced insulin requirements and less weight gain 3, 2