Adding Novolog to Lantus in Diabetes Management
When a patient on Lantus (insulin glargine) requires additional glycemic control, add Novolog (insulin aspart) as prandial insulin starting with 4 units before the largest meal or 10% of the current basal dose, then titrate by 1-2 units every 3 days based on postprandial glucose readings. 1
When to Add Prandial Insulin
Add Novolog to existing Lantus therapy when:
- A1C remains above target after 3-6 months of optimized basal insulin despite achieving fasting glucose goals of 80-130 mg/dL 1
- Basal insulin dose approaches 0.5-1.0 units/kg/day without achieving glycemic targets, indicating "overbasalization" 1, 2
- Clinical signs of overbasalization appear: bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia episodes, or high glucose variability 1, 2
- Significant postprandial glucose excursions occur (>180 mg/dL) despite controlled fasting glucose 1
Initial Dosing Algorithm
Starting Dose
- Begin with 4 units of Novolog before the largest meal or the meal causing the greatest postprandial glucose excursion 1
- Alternative calculation: Use 10% of the current basal insulin dose 1
- If A1C <8% (<64 mmol/mol): Consider reducing Lantus by 4 units or 10% when adding prandial insulin 1
Administration Timing
- Inject Novolog 5-10 minutes before meals (within 0-15 minutes is acceptable) 3, 4
- Never administer rapid-acting insulin at bedtime due to nocturnal hypoglycemia risk 1, 2
Titration Protocol
Dose Adjustment Schedule
- Increase Novolog by 1-2 units every 3 days based on 2-hour postprandial glucose readings 1
- Alternative: Increase by 10-15% of current dose twice weekly 1
- Target postprandial glucose: <180 mg/dL 1
Hypoglycemia Management
- If hypoglycemia occurs without clear cause: Reduce the corresponding Novolog dose by 10-20% immediately 1
- Treat hypoglycemia with 15 grams of fast-acting carbohydrate 2
Stepwise Intensification
Single Meal Coverage (Initial)
Start with one Novolog injection before the largest meal 1
Two Meal Coverage (If Needed)
If A1C remains above target, add a second Novolog injection before another meal 1
Full Basal-Bolus Regimen
Progress to Novolog before all three meals if glycemic targets are not met 1
Monitoring Requirements
- Check fasting glucose daily to guide Lantus adjustments 1, 2
- Check pre-meal and 2-hour postprandial glucose to guide Novolog titration 1, 2
- Reassess every 3-6 months to avoid therapeutic inertia 1
- Monitor for overbasalization signs at every visit 1
Critical Thresholds and Warnings
Stop Escalating Basal Insulin When:
- Lantus exceeds 0.5 units/kg/day: This signals the need for prandial coverage rather than further basal increases 1, 2
- Bedtime-to-morning glucose differential ≥50 mg/dL: Indicates excessive basal insulin 1, 2
Continue Foundation Therapy
- Maintain metformin unless contraindicated, even when intensifying insulin therapy 1, 2
- Consider adding GLP-1 receptor agonist if not already on one, as combination therapy provides superior outcomes with less hypoglycemia and weight gain 1
Common Pitfalls to Avoid
- Do not continue escalating Lantus beyond 0.5-1.0 units/kg/day without adding prandial coverage—this causes overbasalization with increased hypoglycemia risk 1, 2
- Do not mix Novolog with Lantus in the same syringe due to Lantus's low pH 1, 3
- Do not delay adding prandial insulin when signs of overbasalization are present 1, 2
- Do not discontinue metformin when adding insulin unless contraindicated 1, 2
- Do not use sliding scale insulin as monotherapy—always use scheduled basal-bolus regimens 1, 2
Special Considerations
Injection Technique
- Rotate injection sites within the same region to reduce lipodystrophy risk 3
- Inject Novolog subcutaneously into abdomen, thigh, buttocks, or upper arm 3
- Administer Lantus separately from Novolog—do not mix 1, 3