Discontinuation of Levemir (insulin detemir) and switching strategies

Levemir (insulin detemir) in FlexPen and Penfill cartridge formats is being globally discontinued, with UK NHS supplies ending by December 2026 (1,2):

• a UK safety-critical National Patient Safety Alert (NatPSA) and Department of Health and Social Care (DHSC) notifications mandate no new initiations across UK healthcare settings and require all existing UK patients to be switched to alternative basal insulins by 30 November 2026
• there is no direct bioequivalent or licensed twice-daily analogue alternative to Levemir; switching carries an elevated risk of glucose instability
• switching insulin regimens in UK primary care requires careful specialist support, NHS advice and guidance, or direct specialist diabetes team input, particularly for complex cohorts, type 1 diabetes, and high-risk patients

UK safety directives and supply considerations

• immediate action: cease all new initiations of Levemir immediately across UK primary and secondary care
• mandatory clinical review: all existing UK patients (type 1, type 2, type 3c, gestational diabetes, and pump users) must undergo clinical review prior to switching
• NHS supply diversification: UK prescribers must diversify choices across available alternative brands (e.g., Lantus, Semglee, Toujeo, Tresiba) using the Specialist Pharmacy Service (SPS) Medicines Supply Tool to avoid secondary UK-wide shortages
• UK supply constraints: Abasaglar (glargine U100) and Humulin I (isophane) are under severe UK supply restrictions and cannot support large-scale switching; Tresiba U100 FlexTouch is discontinued (Tresiba U100 cartridges and Tresiba U200 FlexTouch remain available in the UK)

Key principles of switching

• specialist support requirement: switching insulin regimens requires specialist support, NHS advice and guidance pathways, or direct management by community/secondary diabetes specialist teams
• dose reduction strategy: reduce total daily dose (TDD) by 10% to 20% on switching to mitigate initial hypoglycemia risk
  • default to 20% reduction in high-risk patients (impaired hypo awareness, frailty, renal impairment, tight baseline control, or high glucose variability) to ensure maximum safety before titrating upward based on monitoring
  • opt for 10% reduction in stable patients with suboptimal baseline control / elevated fasting glucose or when switching to Toujeo (which often eventually requires a 10% to 18% higher final dose)
• monitoring: historical HbA1c must not be used to guide switches; monitor using capillary blood glucose (CBG; minimum 4 times daily) or continuous glucose monitoring (CGM)
• device and brand prescribing: prescribe alternative insulins by brand name in accordance with UK prescribing safety standards; ensure device training and needle/ancillary compatibility

Alternative options and worked examples

Once-daily Levemir regimens

• preferred options: insulin glargine U100 (Lantus or Semglee)
  • Worked example: Levemir 30 units once daily at bedtime to Lantus 24 units (20% reduction) or 27 units (10% reduction) once daily at bedtime, depending on specific clinical considerations
• alternative option: human isophane insulin (Humulin I) only if no other suitable alternative is clinically appropriate
  • Worked example: Levemir 20 units once daily in morning to Humulin I 16 units (20% reduction) or 18 units (10% reduction) once daily in morning, depending on specific clinical considerations

Twice-daily Levemir regimens (equal doses; <20% difference)

• preferred options: ultralong-acting insulins once daily (insulin degludec/Tresiba U100/U200 or insulin glargine U300/Toujeo) or off-label twice-daily glargine U100 (Lantus/Semglee)
• calculation: calculate total daily dose (TDD) of Levemir, apply 10-20% reduction, and administer as a single daily dose (or split twice daily for off-label glargine U100)
  • Worked Example A: Levemir 20 units twice daily (40 units TDD) to Toujeo or Tresiba 32 units (20% reduction) or 36 units (10% reduction) once daily, depending on specific clinical considerations
  • Worked Example B: Levemir 18 units AM / 15 units PM (33 units TDD) to Tresiba 27 units (20% reduction) or 30 units (10% reduction) once daily, depending on specific clinical considerations (or off-label Lantus 14-15 units twice daily)

Twice-daily Levemir rRegimens (unequal doses; >20% difference)

• official calculation rule: as explicitly stated in joint PCDOS/ABCD clinical guidance, "To calculate an appropriate dose of alternative once daily insulin (either insulin glargine U100 or ultralong basal insulin such as Toujeo / Tresiba), take the lowest of the two Levemir doses and multiply this by 2, and consider this the maximum safe daily dose initially. Reduce this maximum safe daily dose by 10-20% as the initial new dose of basal insulin."
• type 1 / type 3c diabetes: Toujeo, Tresiba, or off-label twice-daily glargine U100 (Lantus/Semglee)
  • calculation rule: calculate maximum safe daily dose (lowest single Levemir dose x 2), then reduce by 10-20% for starting once-daily dose
  • Worked Example: Levemir 20 units AM / 14 units PM to lowest dose 14 x 2 = 28 units max safe dose to Lantus/Toujeo/Tresiba 22 units (20% reduction) or 25 units (10% reduction) once daily, depending on specific clinical considerations
• type 2 diabetes: Lantus, Semglee, Toujeo, Tresiba, or Humulin I twice daily (reduced by 10-20% per dose) only if no suitable alternative
  • Worked Example: Levemir 36 units AM / 20 units PM to Humulin I 29 units AM / 16 units PM (20% reduction) or 32 units AM / 18 units PM (10% reduction), depending on specific clinical considerations

Insulin pump backup basal insulin

• preferred option: insulin glargine U100 (Lantus or Semglee)
• rationale: backup basal insulin is needed for acute pump failure (<72 hours); ultralong-acting insulins (Tresiba/Toujeo) are avoided as their extended half-life complicates pump re-initiation

Specialist referral and follow-up pathways

• mandatory UK specialist review: all pediatric/adolescent patients (<25 years), pregnant women, and patients with severe renal impairment (eGFR < 30 mL/min) must be reviewed by specialist NHS diabetes services
• follow-up schedule: review high-risk patients within 1-2 weeks and stable patients within 2-3 weeks to titrate doses, verify device competence, and review sick-day rules

References

1. Primary Care Diabetes & Obesity Society (PCDOS), Association of British Clinical Diabetologists (ABCD). Discontinuation of Levemir (Insulin detemir) Flexpen and Penfill Clinical Guideline. Version 2. Published May 27, 2026.
2. Department of Health & Social Care (DHSC). National Patient Safety Alert: Levemir (insulin detemir) FlexPen 100units/ml pre-filled pens and Penfill 3ml cartridges discontinuation. Reference NatPSA/2026/006/DHSC. Issued October 1, 2026.