How is the Lantus (insulin glargine) dose calculated?

Calculating Lantus (Insulin Glargine) Dose

The optimal starting dose of Lantus (insulin glargine) is 0.1-0.25 units/kg/day for patients with type 2 diabetes, with subsequent titration based on fasting glucose levels. 1

Initial Dosing Guidelines

Type 2 Diabetes

• Starting dose: 0.1-0.25 units/kg/day as a single daily injection 1
• For patients transitioning from oral medications to insulin therapy, begin with a conservative dose
• Administer at the same time each day for consistent blood glucose control

Type 1 Diabetes

• Starting dose: 0.4-1.0 units/kg/day of total insulin 1
• Typically, 50% of total daily insulin is given as basal insulin (Lantus)
• Remaining 50% is distributed as rapid-acting insulin before meals

Dose Titration Algorithm

1. Monitor fasting blood glucose daily during the titration phase 1
2. Adjust dose every 3 days based on the following schedule:
   • Increase by 2 units if fasting glucose remains above target
   • Increase by 4 units (or 5-10% of current dose) if glucose >200 mg/dL 1
   • Decrease by 10-20% if hypoglycemia occurs 1
3. Continue adjusting until target fasting glucose (90-150 mg/dL) is achieved without hypoglycemia

Practical Formula for Dose Calculation

A simplified formula derived from clinical data 2 can be used:

Optimal daily dose = Starting dose (0.15 × weight in kg) + Incremental dose (baseline HbA1c - target HbA1c + 2)

This formula provides a practical approach to both initial dosing and subsequent adjustments based on HbA1c targets.

Special Considerations

• Renal impairment: Reduce starting dose to 0.114 units/kg/day in patients with eGFR <60 mL/min/1.73m² 2
• Retinopathy: Consider lower starting dose of 0.120 units/kg/day 2
• Women: May require slightly lower starting dose (0.135 units/kg/day) 2
• Patients on sulfonylureas: Consider reduced starting dose of 0.132 units/kg/day 2
• Elderly patients: Use more conservative targets and starting doses to minimize hypoglycemia risk

Administration Guidelines

• Lantus provides relatively constant basal insulin levels without pronounced peaks for approximately 24 hours 3
• Can be administered at any time of day, but should be given at the same time daily
• Do not mix Lantus with other insulins in the same syringe 4
• For very insulin-resistant patients requiring large doses, consider splitting into two daily injections 4

Common Pitfalls to Avoid

• Underdosing: Starting with too low a dose can delay achieving glycemic targets
• Aggressive titration: Increasing dose too quickly can lead to hypoglycemia
• Relying solely on correction insulin: Lantus should provide basal coverage, with additional rapid-acting insulin for mealtime coverage when needed 1
• Inconsistent timing: Administering Lantus at different times daily can lead to variable glucose control

Lantus provides effective basal insulin coverage with lower risk of nocturnal hypoglycemia compared to NPH insulin 3, 5, making it an excellent choice for establishing baseline glycemic control in both type 1 and type 2 diabetes.