What is a reasonable fixed daily dose of Novolog (insulin aspart) for an adult patient with type 2 diabetes taking 160 units of 70/30 insulin daily, when adding Novolog TID (three times a day) to their regimen?

Fixed Daily Dose of Novolog TID for Patients on 70/30 Insulin

For a patient taking 160 units of 70/30 insulin daily who needs to add Novolog TID at a fixed dose, start with 4 units of Novolog before each of the three main meals (12 units total daily), while reducing the 70/30 insulin dose by approximately 10-20% to prevent hypoglycemia. 1

Understanding the Current Regimen

Your patient is currently on 160 units of 70/30 insulin daily, which provides both basal and prandial coverage in a fixed ratio. This high total daily dose (likely >1 unit/kg/day for most patients) suggests significant insulin resistance and inadequate glycemic control, particularly if you're considering adding mealtime insulin. 1, 2

Initial Novolog Dosing Strategy

Starting Dose Calculation

• Begin with 4 units of Novolog before each meal (breakfast, lunch, and dinner), totaling 12 units of additional prandial coverage daily 1, 2
• Alternatively, calculate 10% of the current basal insulin component: If using 160 units of 70/30, the approximate basal component is ~112 units (70% of 160), so 10% would be ~11 units divided among three meals 1, 2

Adjusting the 70/30 Regimen

When adding separate prandial insulin, you must reduce the 70/30 dose to avoid stacking insulin and causing hypoglycemia:

• Reduce the total 70/30 dose by 10-20% (decrease by 16-32 units total) 1, 2
• This reduction accounts for the additional prandial coverage you're now providing with Novolog 1

Titration Algorithm

Once initiated, adjust the Novolog doses systematically:

• Increase each meal's Novolog dose by 1-2 units every 3 days based on 2-hour postprandial glucose readings for that specific meal 1, 2
• Target postprandial glucose <180 mg/dL 1
• If hypoglycemia occurs, reduce the corresponding dose by 10-20% immediately 1, 2

Critical Threshold Considerations

This patient's total daily insulin dose of 160 units likely exceeds 0.5-1.0 units/kg/day, which is a critical threshold signaling "overbasalization." 1, 2 At this point, continuing to escalate basal insulin without adequate prandial coverage leads to:

• Increased hypoglycemia risk 1, 2
• Suboptimal glycemic control 1, 2
• High glucose variability 1, 2
• Bedtime-to-morning glucose differential ≥50 mg/dL 1, 2

Alternative Approach: Consider Transitioning to Basal-Bolus

Given the high total daily dose, a more comprehensive approach may be warranted:

• Calculate 50% of current total daily dose (80 units) as basal insulin using a long-acting analog like glargine or degludec 1, 2
• Provide the remaining 50% (80 units) as prandial insulin, divided among three meals (~27 units per meal as a starting point) 1, 2
• This basal-bolus approach provides superior glycemic control compared to premixed insulin regimens, with lower hypoglycemia rates 1, 3, 4

Monitoring Requirements

• Daily fasting and pre-meal blood glucose monitoring is essential during titration 1, 2
• Check 2-hour postprandial glucose to guide individual meal dose adjustments 1, 2
• Reassess every 3 days during active titration 1, 2
• Monitor for hypoglycemia, particularly nocturnal episodes 1, 2

Foundation Therapy Optimization

Ensure the patient is on metformin at maximum tolerated dose (up to 2000-2500 mg daily) unless contraindicated, as this combination reduces total insulin requirements and provides superior glycemic control with less weight gain. 1, 2

Common Pitfalls to Avoid

• Never add prandial insulin without reducing the premixed insulin dose - this causes dangerous insulin stacking and hypoglycemia 1, 2
• Do not use sliding scale insulin as the sole prandial coverage - scheduled prandial doses are superior to reactive correction-only approaches 1, 2
• Avoid administering rapid-acting insulin at bedtime - this significantly increases nocturnal hypoglycemia risk 1, 2
• Do not continue premixed insulin indefinitely when basal-bolus therapy is indicated - randomized trials show basal-bolus provides better outcomes with lower hypoglycemia rates 1, 3, 4

Patient Education Essentials

Provide comprehensive education on:

• Proper injection technique and site rotation 1, 2
• Hypoglycemia recognition and treatment with 15 grams of fast-acting carbohydrate 1, 2
• Timing of Novolog administration: 0-15 minutes before meals for optimal postprandial control 1, 2
• Self-monitoring of blood glucose and recording values to guide dose adjustments 1, 2