Initial Dosing of Insulin Glargine
The recommended initial dose of insulin glargine is 10 units per day or 0.1-0.2 units/kg of body weight for insulin-naive patients. 1
Dosing Guidelines Based on Patient Type
For Type 2 Diabetes Patients
- Start with 10 units per day or 0.1-0.2 units/kg of body weight 1, 2
- Continue oral antidiabetic medications, particularly metformin 1
- Administer once daily, typically at bedtime, but can be given at any time of day 1, 3
- Individuals with type 2 diabetes generally require higher daily doses (up to 1 unit/kg) due to insulin resistance 4
For Type 1 Diabetes Patients
- Initial dose typically ranges from 0.4 to 1.0 units/kg/day 4
- Generally, 50% of the total daily insulin requirement should be basal insulin and 50% as prandial insulin 4
- A typical starting dose in metabolically stable patients is 0.5 units/kg/day, with half as basal insulin 4
For Elderly Patients
- Use lower initial doses (0.1 units/kg/day) to minimize hypoglycemia risk 1
- Consider simplified insulin regimens as outlined in the Standards of Care for older adults 4
Titration Protocol
After initiating insulin glargine, adjust the dose as follows:
- Increase dose by 2 units once or twice weekly until fasting glucose target is reached 1
- If 50% of fasting glucose values are above target, increase by 2 units 4
- If more than 2 fasting glucose values per week are below 80 mg/dL (4.4 mmol/L), decrease dose by 2 units 4, 1
- Target fasting glucose range: 90-150 mg/dL (5.0-8.3 mmol/L) for older adults 4; 80-130 mg/dL for general population 2
Special Considerations
Overbasalization
- Avoid continuing to escalate basal insulin dose without meaningful reduction in fasting glucose 2
- If basal insulin has been titrated to an acceptable fasting glucose level (or if dose exceeds 0.5 units/kg/day) and A1C remains above target, consider advancing to combination injectable therapy 4
Timing of Administration
- Insulin glargine can be administered at any time of day, provided it's given at the same time each day 1, 3
- In some cases, splitting the dose to twice daily may be beneficial for patients experiencing hypoglycemia despite dose titration 5
Concentrated Formulations
- U-300 glargine and U-200 degludec are concentrated formulations that allow higher doses per volume 4
- These may be more comfortable for patients requiring large doses of insulin 4
Common Pitfalls to Avoid
- Delayed titration: Timely dose adjustment is critical for achieving glycemic targets 1
- Ignoring hypoglycemia: Reduce dose if fasting glucose falls below target or nocturnal hypoglycemia occurs 1
- Premature discontinuation of oral agents: Metformin should generally be continued when initiating basal insulin 1
- Mixing with other insulins: Insulin glargine should not be mixed with other insulin formulations due to its low pH 1, 3
By following these evidence-based guidelines for insulin glargine initiation, clinicians can effectively manage hyperglycemia while minimizing the risk of adverse events such as hypoglycemia.