Equivalent Dose Conversion: Basaglar to Lantus
The equivalent dose of Lantus for a patient taking 40 units of Basaglar at night is 40 units, administered once daily at the same time each evening.
Direct Unit-for-Unit Conversion
Basaglar and Lantus are both insulin glargine 100 units/mL formulations with equivalent potency—the FDA label for Lantus explicitly states that it has "potency that is approximately the same as the potency of human insulin," and both products contain the same active ingredient at the same concentration. 1
No dose adjustment is required when switching between these two products because they are biosimilar formulations of insulin glargine U-100, demonstrated to have similar efficacy and safety profiles in clinical trials. 2
The patient should continue taking 40 units subcutaneously once daily at the same time each evening, maintaining the same injection timing to preserve the 24-hour basal insulin coverage. 1
Clinical Monitoring After Conversion
Check fasting blood glucose daily for the first 3–7 days after switching to Lantus to confirm adequate basal coverage and rule out unexpected hypoglycemia or hyperglycemia. 3
Target fasting plasma glucose of 80–130 mg/dL (4.4–7.2 mmol/L) should guide any subsequent dose adjustments. 4
If fasting glucose remains consistently above 130 mg/dL for ≥3 days, increase the Lantus dose by 2 units every 3 days until target is achieved. 3
If any glucose reading falls below 70 mg/dL, reduce the basal dose by 10–20% (i.e., from 40 units to 32–36 units) to prevent recurrent hypoglycemia. 3, 4
Key Safety Considerations
Rotate injection sites within the same anatomical region (abdomen, thigh, or deltoid) to reduce lipodystrophy risk, though absorption rates are clinically equivalent across these sites. 1
Do not mix or dilute Lantus with any other insulin or solution, as this alters its pharmacokinetic profile unpredictably. 1
Ensure the patient understands that this is a straightforward 1:1 conversion with no expected change in glycemic control, but emphasize the importance of monitoring during the transition period. 2