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

Converting from Tresiba to Lantus: Dosing Recommendations

When converting from Tresiba (insulin degludec) to Lantus (insulin glargine), use a 1:1 conversion ratio as the starting point, but consider a 10-20% dose reduction initially to minimize hypoglycemia risk.

Conversion Principles

The conversion from Tresiba to Lantus requires careful consideration due to their different pharmacokinetic profiles:

• Tresiba (insulin degludec) has an ultra-long duration of action (>42 hours) with minimal peaks
• Lantus (insulin glargine) has a duration of approximately 24 hours with a relatively flat profile

Step-by-Step Conversion Algorithm:

1. Initial conversion: Start with a 1:1 unit conversion from Tresiba to Lantus

2. Consider dose reduction: Reduce the initial Lantus dose by 10-20% if the patient:

   • Has a history of hypoglycemia
   • Is elderly
   • Has renal or hepatic impairment
   • Has tight glycemic control (HbA1c <7%)

3. Timing of administration:

   • Administer Lantus at the same time each day
   • Can be given any time of day, but consistency is important

4. Monitoring protocol:

   • Check fasting blood glucose daily for the first week
   • Adjust Lantus dose by 2-4 units every 3-7 days based on fasting glucose targets
   • Monitor for hypoglycemia, especially at night

Important Clinical Considerations

Pharmacokinetic Differences

Tresiba has a longer duration of action than Lantus, which may result in overlapping insulin effects during the transition. The British Journal of Anaesthesia guidelines note that patients transitioning between insulin types may require careful monitoring during the transition period 1.

Hypoglycemia Risk

Studies have shown that insulin degludec (Tresiba) has a lower risk of hypoglycemia, particularly nocturnal hypoglycemia, compared to insulin glargine (Lantus) 2, 3. Therefore, patients may experience different hypoglycemia patterns after switching.

Special Populations

• Hospitalized patients: More frequent monitoring may be required during the transition
• Patients with type 1 diabetes: Must maintain continuous insulin coverage; never discontinue basal insulin completely
• Elderly patients: Consider starting with a 20% dose reduction when switching to Lantus

Practical Tips

• Do not mix Lantus with other insulins due to its acidic pH 1, 4
• Lantus should be administered subcutaneously once daily at the same time each day
• If a patient was on twice-daily Tresiba, the total daily dose should be consolidated into a single Lantus dose
• Patients should be educated about the different onset, peak, and duration profiles of these insulins 1

Common Pitfalls to Avoid

• Abrupt transitions: Don't discontinue Tresiba and start Lantus the next day without overlap consideration
• Failure to adjust: Don't maintain the same dose without monitoring and adjusting based on glucose readings
• Inconsistent timing: Lantus requires more consistent timing than Tresiba due to its shorter duration of action
• Ignoring patient factors: Individual factors like renal function, age, and activity level should influence the conversion ratio

By following these guidelines and closely monitoring blood glucose levels during the transition period, patients can safely switch from Tresiba to Lantus while maintaining glycemic control and minimizing hypoglycemia risk.