- Article
- Source: Campus Sanofi
- 20 Apr 2026
How to Start and Switch Insulin: an HCP's guide
Toujeo® (insulin glargine 300 units/ml) Prescribing Information
Lantus® (insulin glargine 100 units/ml) Prescribing Information
With the discontinuation of Levemir® (insulin detemir) this December, decisions around which alternative basal insulin to initiate or switch patients to are becoming increasingly important.
The following guidance reflects the joint recommendations of the Association of British Clinical Diabetologists (ABCD) and Primary Care Diabetes & Obesity Society (PCDO) on the discontinuation of Levemir, applied to initiating and switching patients to Toujeo® (insulin glargine 300 units/mL) in clinical practice.1 Toujeo® remains one of the preferred options in certain patient circumstances.1
Starting patients on Toujeo®2
Toujeo® is a basal insulin for once daily administration at any time of the day, preferably at the same time every day. When needed, patients can administer Toujeo® up to 3 hours before or after their usual time of administration. The dose regimen (dose and timing) should be adjusted according to individual response.2
Toujeo® is indicated for the treatment of diabetes mellitus in adults, adolescents and children from the age of 6 years.2
Patients with type 1 diabetes mellitus²
Toujeo® is to be used once daily with meal time insulin and requires individual dose adjustments. Toujeo® must be combined with short-/rapid acting insulin to cover mealtime insulin requirements.
Patients with type 2 diabetes mellitus²
The recommended daily starting dose is 0.2 units/kg followed by individual dose adjustments. Toujeo® can also be given together with other anti-hyperglycaemic medicinal products.
Switching from different basal insulins to Toujeo®2
Whenever switching insulins, close metabolic monitoring is recommended during the switch and in the initial weeks thereafter, with potential dose adjustments and adjustments required to the patients’ treatment regimen.
- 80% of total daily dose as Toujeo®
Example: 20 units morning + 15 units evening determir = 28 units Toujeo® (80% of 35)
- Unit to unit based on the previous basal insulin dose
- Insulin (glargine 100 units/mL) and Toujeo® are not bioequivalent and are not directly interchangeable
- Unit to unit based on the previous dose
- ~10-18% higher dose adjustment may be required
Example: Lantus® (insulin glargine 100 units/mL) 40 units once daily = 40 units Toujeo® (may need up to 47 units)
Practical Implementation1
Time pressures in clinical practice bring competing demands. The guidance below provides key considerations to support patients at the different stages of their transition.
- Check the DHSC Medicines Supply Notification and availability via the SPS Medicines Supply Tool.
- People with allergies to alternative insulins should be referred to local allergy or diabetes services as required.
- Evaluate co-morbidities, and prioritise those in high-risk groups, such as those below:
- Impaired hypoglycaemia awareness
- High glucose variability on CGM, history of severe hypoglycaemia or recurrent diabetic ketoacidosis (DKA)
- Evidence of lipohypertrophy at injection sites
- Frailty and/or older age
- Children and adolescents
- Renal or severe hepatic impairment
- Cognitive or functional impairment
- Learning difficulties or low health literacy
- Visual impairment and manual dexterity problems
- High alcohol intake or binge drinking
- High level of physical activity
- As part of the clinical review, assess whether the current insulin regimen in type 2 diabetes could be optimised by introducing / switching to different insulin types (e.g., rapid-acting, or mixed insulin) or by incorporating non-insulin therapies.
- When switching between insulins, there can be differences between absorption, potency, and action profile, therefore consider reducing doses by 10-20% to avoid the initial risk of hypoglycaemia.
- If lipohypertrophy is detected, considerable dose adjustment is often required when changing injection sites, seek advice and guidance as necessary if unsure.
- When prescribing new insulins, ensure any change in device type is explained to the patient with written product information provided.
- For those with very erratic glucose levels, or disproportionately high insulin doses, assess injection technique and check for evidence of lipohypertrophy at injection sites.
- Education and support should be provided to help individuals self-adjust doses post-switch, where appropriate, along with a check of understanding of sick day rules.
- Ensure adequate safety netting, advising patients to report any concerns about glucose levels after following provided dose adjustment guidance.
- Risk of glucose instability is elevated during insulin changes. A clinical review with CBG/CGM data is helpful.
- Monitoring should rely on capillary blood glucose (CBG) at least four times daily, CGM, and ketone monitoring (where appropriate)—not HbA1c alone.
- People living with diabetes should be reviewed at 2-3 weeks to support with dose titration, as necessary. For those at higher risk of dysglycaemia aim for close clinical review within 1-2 weeks of change where possible.
- If there is uncertainty seek advice and guidance or refer to community / specialist diabetes services as per locally agreed pathways.
- Check the DHSC Medicines Supply Notification and availability via the SPS Medicines Supply Tool.
- People with allergies to alternative insulins should be referred to local allergy or diabetes services as required.
- Evaluate co-morbidities, and prioritise those in high-risk groups, such as those below:
- Impaired hypoglycaemia awareness
- High glucose variability on CGM, history of severe hypoglycaemia or recurrent diabetic ketoacidosis (DKA)
- Evidence of lipohypertrophy at injection sites
- Frailty and/or older age
- Children and adolescents
- Renal or severe hepatic impairment
- Cognitive or functional impairment
- Learning difficulties or low health literacy
- Visual impairment and manual dexterity problems
- High alcohol intake or binge drinking
- High level of physical activity
- As part of the clinical review, assess whether the current insulin regimen in type 2 diabetes could be optimised by introducing / switching to different insulin types (e.g., rapid-acting, or mixed insulin) or by incorporating non-insulin therapies.
- When switching between insulins, there can be differences between absorption, potency, and action profile, therefore consider reducing doses by 10-20% to avoid the initial risk of hypoglycaemia.
- If lipohypertrophy is detected, considerable dose adjustment is often required when changing injection sites, seek advice and guidance as necessary if unsure.
- When prescribing new insulins, ensure any change in device type is explained to the patient with written product information provided.
- For those with very erratic glucose levels, or disproportionately high insulin doses, assess injection technique and check for evidence of lipohypertrophy at injection sites.
- Education and support should be provided to help individuals self-adjust doses post-switch, where appropriate, along with a check of understanding of sick day rules.
- Ensure adequate safety netting, advising patients to report any concerns about glucose levels after following provided dose adjustment guidance.
- Risk of glucose instability is elevated during insulin changes. A clinical review with CBG/CGM data is helpful.
- Monitoring should rely on capillary blood glucose (CBG) at least four times daily, CGM, and ketone monitoring (where appropriate)—not HbA1c alone.
- People living with diabetes should be reviewed at 2-3 weeks to support with dose titration, as necessary. For those at higher risk of dysglycaemia aim for close clinical review within 1-2 weeks of change where possible.
- If there is uncertainty seek advice and guidance or refer to community / specialist diabetes services as per locally agreed pathways.
Dedicated Support
Our UK-based customer care team is available to provide support and information regarding our insulin products via sanoficares@sanofi.com.
This includes information on product availability, storage recommendations, and address general enquiries about our insulin products.
Patient resources and demonstration devices can be requested via sanoficares@sanofi.com or printed from mysanofiinsulin.co.uk.
RePen Recycling Scheme
Sanofi is committed to reducing the environmental impact of diabetes care. The RePen recycling scheme allows patients to return used insulin pens for responsible disposal and recycling.
For more information about the RePen recycling programme and to find your nearest participating location, please visit mysanofiinsulin.co.uk/repen.
References
- Newland-Jones P, Beba H, Kanumilli N, Kelly B, Lindsay R, Mehta F, Milne N, Platts J, Tahir W, Dhatariya K (2025) Discontinuation of Levemir® (Insulin detemir) Flexpen® and Penfill® Clinical Guideline. Primary Care Diabetes & Obesity Society and Association of British Clinical Diabetologists. Available at: https://pcdosociety.org/guidance/levemir-discontinuation [Accessed 7 April 2026]
- Sanofi. Toujeo® 300 units/mL solution for injection in a pre-filled pen - Summary of Product Characteristics (SmPC) 2024.
MAT-XU-2504556-2.0-04/2026