Is 35 units daily of Basaglar (insulin glargine) equivalent to 35 units of Tresiba (insulin degludec)?

Insulin Equivalence: Basaglar vs Tresiba

35 units of Basaglar (insulin glargine) is not equivalent to 35 units of Tresiba (insulin degludec) due to differences in pharmacokinetic profiles and potency.

Pharmacological Differences

Basaglar (insulin glargine) and Tresiba (insulin degludec) are both long-acting basal insulins but have important differences:

• Duration of Action:

  • Basaglar (insulin glargine) has a duration of action up to 24 hours 1
  • Tresiba (insulin degludec) has an ultra-long duration of action exceeding 42 hours 2

• Pharmacodynamic Variability:

  • Tresiba has significantly lower day-to-day variability in glucose-lowering effect compared to insulin glargine
  • Research shows Tresiba has four times lower pharmacodynamic variability than insulin glargine under steady-state conditions (CV 20% vs 82%) 3

• Potency Differences:

  • When administered at the same unit dose, insulin degludec results in higher average glucose values (approximately 29 mg/dL higher) compared to insulin glargine 2

Clinical Implications

Dosing Considerations

When switching between these insulins:

1. Dose Adjustment Needed: Due to the potency differences, patients switching from Basaglar to Tresiba may require dose adjustment.

2. Monitoring Requirements: More frequent blood glucose monitoring is necessary when transitioning between these insulins.

3. Hypoglycemia Risk:

   • Tresiba has been associated with lower rates of nocturnal hypoglycemia compared to insulin glargine 4, 5
   • However, the overall hypoglycemia risk profile differs between the two insulins

Practical Approach for Switching

• When switching from Basaglar to Tresiba, consider starting with a slightly lower dose (approximately 10-20% reduction) based on the evidence of higher glucose values with equivalent units 2

• When switching from Tresiba to Basaglar, close monitoring is essential as the ultra-long duration of Tresiba means its effects may persist for several days after discontinuation

Common Pitfalls to Avoid

1. Assuming Unit-for-Unit Equivalence: The most critical error is assuming these insulins can be exchanged on a unit-for-unit basis.

2. Ignoring Timing Flexibility Differences: Tresiba offers more flexibility in dosing time due to its ultra-long action profile, while Basaglar should be administered at approximately the same time each day.

3. Overlooking Transition Period: When switching between these insulins, patients should be aware that the full effect of the new insulin may take several days to establish, particularly when switching to or from Tresiba.

4. Failing to Adjust Monitoring: More frequent blood glucose monitoring is necessary during the transition period between these insulins.

Both insulins are effective basal insulin options, but they have distinct pharmacological profiles that require careful consideration when switching between them to ensure optimal glycemic control and patient safety.