Toujeo and Lantus Doses Are Not Interchangeable
When switching from Toujeo (insulin glargine U-300) to Lantus (insulin glargine U-100), the recommended starting Lantus dosage should be 80% of the Toujeo dosage that is being discontinued. 1
Understanding the Differences
- Toujeo (insulin glargine U-300) is three times more concentrated than Lantus (insulin glargine U-100), with a more stable and prolonged pharmacokinetic profile 2
- U-300 glargine has a longer duration of action than U-100 glargine but modestly lower efficacy per unit administered, requiring dose adjustments when switching between formulations 3
- The two insulin formulations are not bioequivalent, and the daily insulin requirement is slightly higher with Toujeo (insulin glargine U-300) than with Lantus (insulin glargine U-100) 4
Clinical Implications
- When switching from Toujeo to Lantus, the FDA label specifically recommends reducing the dose to 80% of the previous Toujeo dose 1
- Patients receiving Toujeo typically require approximately 10-12% more insulin to achieve the same glycemic control as those on Lantus 5, 6
- Despite differences in dosing, both formulations achieve comparable glycemic control in patients with type 1 or type 2 diabetes 6
Safety Considerations
- Improper conversion between insulin concentrations can lead to significant dosing errors and potential hypoglycemia 2
- During changes to a patient's insulin regimen, increased frequency of blood glucose monitoring is essential 1
- Toujeo is associated with a lower risk of nocturnal hypoglycemia compared to Lantus in insulin-experienced patients with type 2 diabetes 6, 7
Practical Conversion Guidelines
- When switching from Lantus to Toujeo: The initial Toujeo dose will likely need to be higher than the previous Lantus dose (approximately 10-12% higher) 5
- When switching from Toujeo to Lantus: Reduce the dose to 80% of the previous Toujeo dose 1
- After switching between formulations, careful dose titration based on blood glucose monitoring is necessary to achieve optimal glycemic control 4
Common Pitfalls to Avoid
- Assuming a 1:1 conversion between Toujeo and Lantus can lead to either hypoglycemia (if switching from Toujeo to Lantus without dose reduction) or hyperglycemia (if switching from Lantus to Toujeo without dose increase) 4, 6
- Failing to increase monitoring frequency during the transition period between insulin formulations 1
- Not informing patients about the need for dose adjustments when switching between these insulin products 4