NPH to Lantus Conversion
When converting from twice-daily NPH to once-daily Lantus, reduce the total daily NPH dose by 20% (use 80% of the total NPH dose) to minimize hypoglycemia risk. 1
Conversion Strategy Based on NPH Regimen
Twice-Daily NPH to Once-Daily Lantus
- Calculate the total daily NPH dose (morning + evening doses combined) 1
- Multiply by 0.8 (80%) to determine the starting Lantus dose 1
- This conservative approach reduces hypoglycemia risk, which is the primary safety advantage of Lantus over NPH 2, 3
- Administer Lantus once daily at bedtime, morning, or any convenient time for the patient 2
Once-Daily Bedtime NPH to Once-Daily Lantus
- Use a 1:1 unit-for-unit conversion (same dose) 1
- This approach is appropriate when NPH is already given once daily at bedtime 1
Post-Conversion Titration Protocol
Target Glucose Goals
- Aim for fasting glucose <130 mg/dL (ideally <100 mg/dL for optimal HbA1c <7%) 4
- Target daytime glucose 140-180 mg/dL 5
Dose Adjustment Algorithm
- If fasting glucose remains elevated: Increase Lantus by 2 units every 3 days until reaching target without hypoglycemia 1
- If hypoglycemia occurs (<70 mg/dL): Immediately reduce the dose by 10-20% 1, 5
- Monitor blood glucose every 2-4 hours for the first 24-48 hours after conversion to identify patterns 5
Special Population Considerations
Patients with Renal Impairment
- Start with 80% of the previous NPH dose regardless of whether NPH was once or twice daily 1
- Decreased insulin clearance increases hypoglycemia risk in this population 1
Obese or Insulin-Resistant Patients
- May require twice-daily Lantus dosing due to high insulin volumes needed 2
- Consider splitting the dose if glycemic control is suboptimal with once-daily administration 2
Labile Type 1 Diabetes
- Often most effective when given as two daily injections rather than once daily 2
Monitoring Requirements
Assessment Parameters
- Evaluate bedtime-to-morning glucose differential to assess adequacy of basal insulin coverage 1
- Monitor for presence and timing of hypoglycemia episodes 1
- Check fasting glucose as the primary indicator for dose adjustments 4
Safety Considerations
- Prescribe glucagon for emergent hypoglycemia, especially in high-risk patients 1
- The major advantage of Lantus is lower frequency of hypoglycemic reactions, particularly nocturnal hypoglycemia, compared to NPH 2, 3, 6
- Lantus provides approximately 24 hours of basal coverage without pronounced peaks, unlike NPH which peaks at 4-6 hours 5, 2
Common Pitfalls to Avoid
- Do not mix Lantus with short-acting insulin in the same syringe - Lantus coprecipitates with other insulins, requiring separate injections 2
- Do not use a 1:1 conversion for twice-daily NPH - This increases hypoglycemia risk; always use 80% of total daily dose 1
- Do not delay dose reduction if hypoglycemia occurs - Reduce by 10-20% immediately rather than waiting 1, 5
- Remember that Lantus does not treat postprandial hyperglycemia - Continue or add mealtime rapid-acting insulin as needed 2