How much Lantus (insulin glargine) is needed for a patient taking 42 units daily for 90 days?

Calculating Lantus (Insulin Glargine) Supply for 90 Days

For a patient taking 42 units of Lantus daily, they will need 11.34 milliliters of insulin glargine for a 90-day supply.

Calculation Process

• Lantus (insulin glargine) is available in a concentration of 100 units per milliliter (U-100) 1
• To calculate the daily volume needed:
  • 42 units ÷ 100 units/mL = 0.42 mL per day 1
• For a 90-day supply:
  • 0.42 mL × 90 days = 37.8 mL total volume needed 1

Practical Dispensing Considerations

• Lantus is typically dispensed in:
  • 10 mL vials (1000 units per vial) 1
  • 3 mL prefilled pens (300 units per pen) 1
• For a 90-day supply at 42 units daily (3780 total units):
  • Using vials: 4 vials would be needed (4000 units total)
  • Using pens: 13 pens would be needed (3900 units total) 1

Important Clinical Considerations

• Ensure proper storage of insulin:
  • Unopened insulin should be refrigerated (36-46°F or 2-8°C) 1
  • In-use vials/pens can be kept at room temperature (below 86°F or 30°C) for up to 28 days 1
• Patients should be instructed on proper injection technique and site rotation to maintain consistent absorption 2
• Regular blood glucose monitoring is essential for patients on basal insulin therapy 1

Potential Pitfalls to Avoid

• Not accounting for potential dose adjustments when calculating long-term supplies 1
• Failing to consider insulin wastage during administration 1
• Not providing adequate education on proper insulin storage and handling 1