Calculating Lantus Volume to Dispense
For a prescription of 10 units of Lantus at a concentration of 100 units/mL, you should dispense 0.1 mL per dose.
Volume Calculation
The calculation is straightforward using the formula:
Volume (mL) = Desired Units ÷ Concentration (units/mL)
- 10 units ÷ 100 units/mL = 0.1 mL 1
This means each morning injection will be 0.1 mL of Lantus solution.
Practical Dispensing Considerations
Standard Pen Devices
- Lantus is typically available in pre-filled pen devices (SoloStar) that deliver insulin in unit increments, not milliliters 1
- Patients using pens simply dial to 10 units on the pen device without needing to measure volume 1
- Each Lantus SoloStar pen contains 3 mL (300 units total), providing 30 days of therapy at 10 units daily 1
Vial and Syringe Method
- If dispensing from a 10 mL vial (1000 units total), the patient draws up to the 10-unit mark on an insulin syringe, which corresponds to 0.1 mL 1
- Standard U-100 insulin syringes are marked in units, making volume measurement automatic 1
- A 10 mL vial provides 100 days of therapy at 10 units daily 1
Critical Administration Details
Timing and Consistency
- Lantus should be administered at the same time each day for optimal basal coverage 1
- The 10-unit starting dose is appropriate for insulin-naive type 2 diabetes patients or represents 0.1-0.2 units/kg body weight 1
Storage and Handling
- Unopened vials/pens should be refrigerated; once in use, they can be kept at room temperature for up to 28 days 1
- Never dilute or mix Lantus with other insulins due to its acidic pH 1