What alternative long‑acting basal insulin can replace the discontinued insulin degludec FlexPen (Tresiba FlexTouch)?

Alternative Long-Acting Basal Insulin to Replace Insulin Degludec FlexPen

If insulin degludec FlexPen (Tresiba FlexTouch) has been discontinued, insulin glargine U-100 (Lantus, Basaglar, or biosimilar follow-on products) is the most appropriate alternative long-acting basal insulin for most patients, offering comparable 24-hour coverage with established safety and efficacy. 1

Primary Alternative: Insulin Glargine U-100

Insulin glargine U-100 provides once-daily basal coverage with a peakless profile lasting approximately 24 hours, making it the most direct replacement for degludec in clinical practice. 1

• Glargine U-100 is available as branded products (Lantus) or biosimilar follow-on products at significantly lower cost ($118-323 per 1,000 units for biosimilars versus $407 for degludec) 1
• Conversion from degludec to glargine U-100 can typically be done unit-for-unit with subsequent adjustment based on glucose monitoring 2
• For patients in very tight glycemic control or at high hypoglycemia risk, reduce the initial glargine dose by 10-20% when converting 2

Alternative Options Based on Clinical Context

For Patients at High Risk of Nocturnal Hypoglycemia

If the patient was specifically on degludec due to recurrent nocturnal hypoglycemia, consider insulin glargine U-300 (Toujeo) as the preferred alternative. 1, 3

• U-300 glargine provides longer duration of action than U-100 glargine with more stable 24-hour coverage 3
• U-300 glargine demonstrates significantly lower rates of clinically significant hypoglycemia (<54 mg/dL) compared to U-100 glargine in head-to-head trials 3
• U-300 glargine requires approximately 10-18% higher daily doses compared to U-100 glargine due to modestly lower efficacy per unit administered 1, 4

For Cost-Constrained Situations

NPH insulin represents the most cost-effective basal insulin alternative when hypoglycemia risk is not elevated, available for approximately $25-165 per vial. 1, 2

• NPH achieves equivalent glycemic control to glargine but requires twice-daily dosing in most patients 2, 5
• NPH carries higher risk of nocturnal hypoglycemia compared to long-acting analogs due to its peak effect 1, 5
• The World Health Organization suggests NPH as first-line insulin therapy, with long-acting analogs reserved for those experiencing frequent severe hypoglycemia 2

Conversion Protocol When Switching from Degludec

Standard Conversion Approach

• Convert unit-for-unit from degludec to glargine U-100 for most patients 2
• Administer glargine U-100 at the same time each day, preferably in the evening 1
• Monitor fasting glucose daily during the first 2 weeks after conversion 4

Titration After Conversion

• Increase glargine by 2 units every 3 days if fasting glucose is 140-179 mg/dL 1, 4
• Increase glargine by 4 units every 3 days if fasting glucose is ≥180 mg/dL 1, 4
• Target fasting plasma glucose of 80-130 mg/dL 1

Critical Threshold Monitoring

When basal insulin exceeds 0.5 units/kg/day and A1C remains above target, consider advancing to combination injectable therapy with GLP-1 receptor agonists or adding prandial insulin rather than continuing to escalate basal insulin alone. 1, 3, 2

• Clinical signals of overbasalization include basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability 3, 2

Important Caveats

• Degludec's ultra-long duration of action (>42 hours) means residual insulin activity may persist for several days after discontinuation, requiring careful monitoring during the transition period 6, 7
• Patients who were benefiting from degludec's flexible dosing schedule (allowing 8-40 hours between doses) will need to maintain strict once-daily timing with glargine 6, 7, 8
• The lower nocturnal hypoglycemia risk observed with degludec compared to glargine U-100 in clinical trials may necessitate closer glucose monitoring during the first weeks after conversion 1, 7