Starting Dose of Humalog with Lantus
For patients with type 1 diabetes on a basal-bolus regimen, start with a total daily insulin dose of 0.5 units/kg/day, giving approximately 50% as Lantus (basal) once daily and 50% as Humalog (prandial) divided among meals. 1, 2
Type 1 Diabetes Dosing Algorithm
Total Daily Insulin Calculation
- Metabolically stable patients: Start with 0.5 units/kg/day total insulin 1, 3
- Newly diagnosed or post-ketoacidosis: May require 0.4-1.0 units/kg/day, with higher doses immediately following DKA 1, 3
- Honeymoon phase or residual beta-cell function: Use lower doses of 0.2-0.6 units/kg/day 1
Basal-Bolus Split
- Lantus (basal): 40-50% of total daily dose, given once daily at the same time 1, 2
- Humalog (prandial): 50-60% of total daily dose, divided among three meals 1
- Distribute prandial insulin based on carbohydrate content of each meal
- Typical starting point: divide equally among breakfast, lunch, and dinner, then adjust based on postprandial glucose patterns
Practical Example
For a 70 kg patient with type 1 diabetes:
- Total daily dose: 0.5 units/kg/day × 70 kg = 35 units/day
- Lantus: 17-18 units once daily 2
- Humalog: 17-18 units total, split as 5-6 units before each meal 1
Type 2 Diabetes Dosing Algorithm
Starting with Basal Insulin Only
- Initial Lantus dose: 10 units once daily OR 0.1-0.2 units/kg/day 2, 3
- Continue metformin and other oral agents 2
- Titrate Lantus by 2-4 units every 3 days until fasting glucose reaches 80-130 mg/dL 2, 3
When to Add Humalog
Add prandial Humalog when: 2
- Fasting glucose is controlled (80-130 mg/dL) but HbA1c remains above goal after 3-6 months on basal insulin alone
- Basal insulin dose exceeds 0.5 units/kg/day without achieving HbA1c target
- Signs of overbasalization appear (bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, high glucose variability)
Adding Humalog to Existing Lantus
- Start with 4 units of Humalog before the largest meal OR 10% of current basal dose 2
- Titrate by 1-2 units every 3 days based on 2-hour postprandial glucose 2
- Add to additional meals sequentially based on glucose patterns 2
Critical Titration Principles
Lantus Adjustment
- Adjust based on fasting glucose only 2
- Increase by 2 units every 3 days if fasting glucose 140-179 mg/dL 2
- Increase by 4 units every 3 days if fasting glucose ≥180 mg/dL 2
- Target fasting glucose: 80-130 mg/dL 2, 3
Humalog Adjustment
- Adjust based on postprandial glucose 2 hours after meals 2
- Increase by 1-2 units every 3 days until postprandial glucose <180 mg/dL 2
- Each meal's Humalog dose is adjusted independently based on glucose after that specific meal
Common Pitfalls to Avoid
Overbasalization
Stop increasing Lantus and add Humalog when: 2
- Basal insulin exceeds 0.5-1.0 units/kg/day
- Bedtime-to-morning glucose differential ≥50 mg/dL
- Recurrent hypoglycemia despite elevated HbA1c
- Fasting glucose controlled but postprandial glucose remains elevated
Continuing to escalate Lantus beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia leads to increased hypoglycemia risk and suboptimal control 2
Timing Errors
- Humalog must be given immediately before meals (0-15 minutes), not after eating 1
- Lantus should be given at the same time daily for consistent 24-hour coverage 2, 3
- Do not mix Lantus with Humalog in the same syringe due to Lantus's low pH 2
Inadequate Monitoring
- Check fasting glucose daily during Lantus titration 2
- Check pre-meal and 2-hour postprandial glucose when titrating Humalog 2
- Reduce insulin dose by 10-20% immediately if hypoglycemia occurs 2
Special Populations
Pediatric Patients
- Total daily insulin requirements are highly variable in children 1
- Higher doses often needed during puberty 1
- Young children and those in honeymoon phase may require doses as low as 0.2-0.6 units/kg/day 1