How do I transition to basal insulin and determine the daily insulin dose?

How to Transition to Basal Insulin and Determine Daily Dose

Initial Basal Insulin Dosing

Start basal insulin at 10 units per day OR 0.1-0.2 units/kg per day for insulin-naïve patients with type 2 diabetes. 1

• For a 70 kg patient, this translates to 7-14 units daily 1
• Choose between basal analog insulins (glargine, detemir, degludec) or bedtime NPH insulin based on cost and patient-specific factors 1
• Prescribe glucagon for emergent hypoglycemia when initiating insulin 1

Setting Target and Titration Strategy

Establish a fasting plasma glucose (FPG) goal before beginning titration—typically 80-130 mg/dL for most adults. 1

Evidence-Based Titration Algorithm:

• Increase dose by 2 units every 3 days until FPG goal is reached without hypoglycemia 1
• Alternative approach: increase by 1 unit per day for NPH, detemir, and glargine U-100, or 2-4 units once or twice weekly for all basal insulins 2
• Assess adequacy of insulin dose at every visit 1

Hypoglycemia Management During Titration:

• If hypoglycemia occurs, determine the cause 1
• If no clear reason identified, reduce dose by 10-20% 1
• Document all hypoglycemic episodes (blood glucose <70 mg/dL) and adjust the treatment plan 1

Monitoring for Overbasalization

Watch for clinical signals indicating overbasalization rather than continuing to escalate doses indefinitely. 1

Key warning signs include:

• Elevated bedtime-to-morning glucose differential 1
• Elevated postprandial-to-preprandial glucose differential 1
• Hypoglycemia (aware or unaware) 1
• High glucose variability 1

When these occur, consider adding adjunctive therapies (GLP-1 RA, prandial insulin) rather than further increasing basal insulin 1

Special Considerations for Specific Basal Insulins

NPH Insulin:

• Administer at bedtime for most patients 1
• Consider morning dosing for steroid-induced hyperglycemia 1
• Higher risk of hypoglycemia compared to analogs 1

Long-Acting Analogs (Glargine, Detemir, Degludec):

• Glargine U-100/U-300 and degludec: typically once daily 3
• Detemir: may require twice-daily dosing for effective control 4
• When switching from glargine U-100 to U-300, expect to need higher doses (median increase from 30 to 34.5 units) 5
• When switching from glargine U-100 to degludec, doses typically remain similar 5

Transitioning from Other Insulin Regimens

From IV to Subcutaneous Insulin (Hospital Setting):

Administer subcutaneous basal insulin 2 hours before discontinuing IV insulin infusion to prevent rebound hyperglycemia. 1

• Calculate total daily dose based on insulin infusion rate during prior 6-8 hours when stable glycemic goals were achieved 1
• Alternative: use prior home insulin dose or weight-based approach (0.1-0.2 units/kg) 1
• Consider adding low-dose basal analog (0.15-0.3 units/kg) during IV infusion to reduce duration and prevent rebound 1

From Other Basal Insulins:

• Unit-to-unit conversion is appropriate when switching between most basal insulins 1
• Consider 20% dose reduction when transitioning to prevent hypoglycemia, particularly in elderly or renally impaired patients 6
• For patients requiring higher doses (≥0.6 units/kg/day), approximately 50-60% should be basal insulin, 40-50% prandial 6

Common Pitfalls to Avoid

• Never use sliding scale insulin alone without basal coverage—this leads to poor glycemic control 1, 3
• Avoid therapeutic inertia: reassess and modify insulin doses regularly every 3-6 months 1
• Do not continue escalating basal insulin beyond approximately 0.5-1.0 units/kg/day without reassessing the regimen 2
• For patients with renal insufficiency, start with lower doses (0.1 units/kg/day) and titrate cautiously 1, 6
• Ensure proper injection technique and site rotation within the same region (thigh, abdomen, upper arm) 4

When to Add Prandial Insulin

If A1C remains above goal despite optimized basal insulin:

• Start with 4 units per dose, 0.1 units/kg, or 10% of basal insulin dose at the largest meal or meal with greatest postprandial glucose excursion 1, 7
• If A1C <8%, consider reducing basal dose by 4 units or 10% when adding prandial insulin to prevent hypoglycemia 1, 7
• Progress to full basal-bolus regimen (approximately 50% basal, 50% prandial) if needed 7, 3