Converting Levemir 19 Units to Lantus 19 Units
A 1:1 unit conversion from Levemir 19 units nightly to Lantus 19 units nightly is appropriate for most patients, though a 10-20% dose reduction should be considered for high-risk individuals. 1
Standard Conversion Protocol
For patients on once-daily Levemir, convert unit-for-unit to once-daily Lantus. 1 The American Diabetes Association supports this 1:1 conversion approach, as both insulin detemir (Levemir) and insulin glargine (Lantus) are long-acting basal insulin analogues with similar glycemic efficacy. 2
- Clinical trial data demonstrates equivalent HbA1c lowering between glargine and detemir in both type 1 and type 2 diabetes. 3, 4
- Both insulins achieve similar fasting plasma glucose control when dosed appropriately. 3
Critical Consideration: Twice-Daily Levemir Patients
If this patient was previously on twice-daily Levemir, sum both daily doses and reduce by 10-20% when converting to once-daily Lantus. 1 This reduction accounts for the pharmacokinetic differences between the two insulins—many patients require twice-daily detemir dosing to achieve 24-hour coverage, whereas glargine typically provides full 24-hour coverage with once-daily administration. 5, 6
High-Risk Patient Modifications
Reduce the converted dose by 10-20% for the following populations: 1
- Elderly patients (>65 years) 1
- Patients with renal impairment 1
- History of severe hypoglycemia 1
- Poor oral intake or acute illness 1
The rationale for dose reduction in high-risk patients is the lower risk of severe hypoglycemia with glargine compared to NPH insulin (OR 0.65), though direct comparison data between detemir and glargine shows similar hypoglycemia rates. 2
Post-Conversion Monitoring Requirements
Daily fasting blood glucose monitoring is essential during the first 1-2 weeks after conversion. 1 Adjust the dose every 3 days based on fasting glucose values, targeting 80-130 mg/dL. 1
Dose adjustment algorithm: 1
- If fasting glucose is 140-179 mg/dL: increase by 2 units every 3 days
- If fasting glucose is ≥180 mg/dL: increase by 4 units every 3 days
- If hypoglycemia occurs: reduce dose immediately by 10-20% and reassess
Administration Timing
Administer Lantus at the same time each day, typically with the evening meal or at bedtime. 1 This maintains consistency with the previous Levemir bedtime dosing schedule.
Common Pitfalls to Avoid
Do not dilute or mix Lantus with any other insulin or solution due to its low pH diluent. 1, 7 This is a critical safety consideration emphasized by the American Association of Clinical Endocrinologists. 1
Do not assume the conversion will be perfect—individual patient response varies. 4 While meta-analyses show no clinically significant differences in efficacy between detemir and glargine, some patients may require dose adjustments based on their glucose response. 4
Continue metformin and other non-insulin diabetes medications unless contraindicated. 8, 9 The basal insulin conversion does not necessitate changes to the foundation diabetes therapy.