Insulin Glargine SoloStar Pen Supply Calculation
For a 30-day supply at 44 units daily, you will need 5 SoloStar pens.
Calculation Breakdown
Each SoloStar prefilled pen contains exactly 300 units of insulin glargine (3 mL of U-100 insulin) 1
At 44 units per day, one pen lasts: 300 units ÷ 44 units/day = 6.82 days per pen 2
For a 30-day supply: 30 days ÷ 6.82 days per pen = 4.4 pens 2
Rounding up to 5 pens ensures adequate supply and accounts for practical considerations 3
Why 5 Pens (Not 4)
The mathematical calculation yields 4.4 pens, but you cannot dispense a partial pen 2
Prescribing 5 pens provides a buffer for:
- Insulin wastage during pen priming (required before each injection) 3, 1
- Potential insulin remaining in the pen after the last deliverable dose 3
- Premature needle withdrawal, which can result in 2.6-20.2% underdelivery depending on technique 4
- Any doses that may be needed if blood glucose monitoring indicates additional correction doses 5
Total Units Provided
- 5 pens × 300 units per pen = 1,500 units total 2
- Daily requirement: 44 units × 30 days = 1,320 units needed 2
- This provides a 180-unit buffer (approximately 4 days extra), which is appropriate for safe insulin management 3
Important Prescribing Considerations
SoloStar is a disposable prefilled pen that is discarded after all insulin is used 2, 1
Each pen can deliver doses from 1 to 80 units in 1-unit increments 1
Your 44-unit daily dose falls well within the single-injection capacity of the pen 1
Do not attempt to extract insulin from the pen with a syringe, as this will result in incorrect dosing 1
Cost Implications
At median pricing, U-100 glargine prefilled pens cost approximately $77-$109 per 1,000 units (AWP/NADAC) 6
For 1,500 units (5 pens), estimated monthly cost ranges from $116-$164 depending on whether branded or biosimilar products are used 6
Generic/biosimilar glargine pens may offer cost savings, with prices as low as $59-$74 per 1,000 units for some formulations 6