How to Adjust Insulin Dose
Start basal insulin at 10 units daily or 0.1-0.2 units/kg/day, then increase by 2 units every 3 days until fasting glucose reaches 80-130 mg/dL; if hypoglycemia occurs, reduce the dose by 10-20%. 1
Basal Insulin Initiation and Titration
Starting dose:
- Begin with 10 units per day OR 0.1-0.2 units/kg per day, depending on degree of hyperglycemia 1, 2
- For severe hyperglycemia (glucose ≥300 mg/dL or A1C ≥10%), consider 0.3-0.4 units/kg/day 2
Titration schedule based on fasting glucose:
- If fasting glucose ≥180 mg/dL: increase by 4 units every 3 days 2
- If fasting glucose 140-179 mg/dL: increase by 2 units every 3 days 1, 2
- If fasting glucose 80-130 mg/dL: maintain current dose 2
- If >2 fasting values per week <80 mg/dL: decrease by 2 units 2
For hypoglycemia management:
- Determine the cause of hypoglycemia 1
- If no clear reason identified, lower the corresponding insulin dose by 10-20% 1
When to Add Prandial Insulin
Assess at every visit for signs of overbasalization: 1
- Elevated bedtime-to-morning glucose differential
- Elevated postprandial-to-preprandial glucose differential
- Hypoglycemia (aware or unaware)
- High glucose variability
- A1C remains above goal despite optimized basal insulin
Prandial Insulin Initiation and Adjustment
Starting approach:
- Begin with one dose before the largest meal or the meal causing greatest postprandial glucose excursion 1, 2
- Initial dose: 4 units per day OR 10% of current basal insulin dose 1, 2
Titration schedule:
- Increase by 1-2 units OR 10-15% of the dose every 3 days based on pre-meal and 2-hour postprandial glucose readings 1, 2
- For hypoglycemia: determine cause; if no clear reason, lower corresponding dose by 10-20% 1
Progression to full basal-bolus regimen:
- If A1C remains above goal, add prandial insulin before additional meals 1
- Alternative method: calculate total daily insulin dose, give 50% as basal and 50% as prandial (split evenly between three meals) 1
Self-Monitoring Requirements
Daily glucose monitoring is essential during titration: 2
- Check fasting glucose, pre-meal glucose, and 2-hour postprandial glucose
- Reassess every 3 days during active titration 2
- Reassess every 3-6 months once stable 2
Equipping patients with self-titration algorithms based on glucose readings improves glycemic control 1, 3, 4
Special Considerations for NPH Insulin
If using bedtime NPH: 1
- Consider converting to twice-daily NPH if adding prandial insulin
- Total NPH dose = 80% of current bedtime NPH dose
- Distribute as 2/3 before breakfast and 1/3 before dinner
- Add 4 units of short/rapid-acting insulin to each injection OR 10% of reduced NPH dose
Consider switching from NPH to basal analog if: 1
- Patient develops hypoglycemia
- Patient frequently forgets evening NPH administration
- Morning dosing of long-acting basal insulin would improve adherence
Combination Therapy Considerations
If A1C remains above goal on basal insulin alone: 1
- Consider adding GLP-1 receptor agonist before intensifying to prandial insulin 1, 2
- This approach improves A1C while minimizing weight gain and hypoglycemia risk 2
- Fixed-ratio combination products (IDegLira or iGlarLixi) are available 1
Continue metformin when adding or intensifying insulin unless contraindicated 2
Common Pitfalls to Avoid
Avoid these errors:
- Do not use rapid- or short-acting insulin at bedtime 2, 5
- Do not mix or dilute insulin glargine with other insulins due to low pH 2
- Do not reuse or share needles between patients 6
- Do not inject in areas with lipodystrophy, thickened skin, lumps, or damaged skin 6
Injection technique:
- Rotate injection sites within the same region rather than between regions 2
- Use abdomen for fastest absorption 2
- Keep needle in skin for at least 6 seconds after pressing injection button fully 6
Frequency of Adjustments
Weekly adjustments are sufficient and safe for effective insulin therapy 3, 4