What is the recommended conversion dose from Tresiba (insulin degludec) to Lantus (insulin glargine)?

Tresiba to Lantus Conversion

When converting from Tresiba (insulin degludec) to Lantus (insulin glargine), a unit-to-unit (1:1) conversion is recommended as the starting point, with close monitoring for potential dose adjustments.

Understanding the Insulin Properties

Both Tresiba and Lantus are long-acting basal insulins, but they have different pharmacokinetic profiles:

• Tresiba (insulin degludec): Ultra-long-acting with duration >24 hours 1
• Lantus (insulin glargine): Long-acting with duration up to 24 hours 1

Conversion Protocol

Initial Conversion

1. Start with a 1:1 unit conversion (same total daily dose)
2. For example: If patient was on 20 units of Tresiba daily, start with 20 units of Lantus

Monitoring and Adjustment

• Check fasting plasma glucose (FPG) levels daily after conversion
• Target FPG according to individualized goals (typically 3.9-5.0 mmol/L or 70-90 mg/dL)
• Adjust Lantus dose by 10-20% or 2-4 units every 3-4 days until target FPG is reached 1

Special Considerations

Hypoglycemia Risk

• Tresiba has been shown to have less nocturnal hypoglycemia compared to Lantus 2, 3
• When switching to Lantus, be vigilant for potential increased risk of nocturnal hypoglycemia
• If hypoglycemia occurs after conversion, reduce Lantus dose by 10-20% 1

Timing of Administration

• Lantus should be administered at the same time each day
• Unlike Tresiba (which offers flexibility in timing), Lantus requires more consistent timing for optimal effect

Clinical Pearls

• Careful monitoring is essential: The first 3-7 days after conversion require particularly close monitoring of blood glucose
• Patient education: Inform patients about the different properties of Lantus compared to Tresiba, particularly regarding timing of administration
• Consider comorbidities: Patients with renal or hepatic impairment may require lower initial doses when converting
• Avoid gaps in insulin coverage: Administer the first Lantus dose at the time the next Tresiba dose would have been due

Potential Pitfalls

• Assuming identical effects: Despite the 1:1 conversion recommendation, individual responses may vary
• Overlooking the shorter duration: Lantus may not provide the same duration of coverage as Tresiba in some patients
• Neglecting to adjust mealtime insulin: If the patient is on a basal-bolus regimen, mealtime insulin may also need adjustment after the basal insulin conversion

The 1:1 conversion ratio provides a practical starting point, but clinical judgment and glucose monitoring should guide subsequent dose adjustments to optimize glycemic control and minimize hypoglycemia risk.