Levemir to Lantus Conversion
Convert the total daily dose of Levemir to Lantus on a 1:1 unit basis and administer once daily for most patients, but reduce the converted dose by 10-20% for patients at high risk of hypoglycemia or those previously on twice-daily Levemir. 1, 2
Standard Conversion Protocol
For patients on once-daily Levemir: Calculate the total daily Levemir dose and convert unit-for-unit to once-daily Lantus 1. The FDA label confirms that when converting from insulin glargine to Levemir (and by extension, the reverse), the change can be done on a unit-to-unit basis 2.
For patients on twice-daily Levemir: Sum both daily doses of Levemir, then reduce by 10-20% when converting to once-daily Lantus due to differences in dosing requirements between the two insulins 1. This reduction accounts for the fact that some patients with type 2 diabetes may require more Levemir than other basal insulins to achieve equivalent glycemic control 2.
High-Risk Patient Modifications
Reduce the converted dose by 10-20% for the following populations 1:
- Elderly patients (>65 years)
- Patients with renal impairment
- History of severe hypoglycemia
- Poor oral intake or acute illness
Post-Conversion Monitoring Requirements
Daily fasting blood glucose monitoring is essential during the first 1-2 weeks after conversion to assess adequacy of the new dose 1. Make dose adjustments every 3 days based on fasting glucose values, targeting 80-130 mg/dL 1.
Titration algorithm after conversion:
- If fasting glucose is 140-179 mg/dL: increase by 2 units every 3 days 3
- If fasting glucose is ≥180 mg/dL: increase by 4 units every 3 days 3
- If hypoglycemia occurs: reduce dose immediately by 10-20% and reassess the conversion 1
Critical Timing Considerations
Administer Lantus at the same time each day, typically with the evening meal or at bedtime 3. Unlike Levemir, which may require twice-daily dosing in some patients, Lantus is designed for once-daily administration in most cases 2.
Common Pitfalls to Avoid
Do not dilute or mix Lantus with any other insulin or solution due to its low pH diluent 4, 3. This is a critical difference from some other insulin formulations and must be strictly observed.
Do not assume the conversion will be perfectly equivalent. While the 1:1 conversion is the starting point, individual patients may require dose adjustments based on their glycemic response 1, 2. Research indicates that some patients with type 2 diabetes may have required more Levemir than other basal insulins, so the reverse conversion may result in improved glycemic control with less insulin 2, 5.
Monitor for changes in hypoglycemia patterns. Clinical trials demonstrate that insulin detemir is generally associated with lower rates of nocturnal hypoglycemia compared to NPH insulin 6, and conversion patterns may affect hypoglycemia risk during the transition period 1.