Lantus SoloStar Pen Calculation for 30-Day Supply
You need to dispense 6 pens of Lantus SoloStar 100 units/mL for this 30-day prescription.
Calculation Breakdown
Total daily insulin requirement:
- Morning dose: 44 units
- Bedtime dose: 46 units
- Total per day: 90 units 1
Total 30-day requirement:
- 90 units/day × 30 days = 2,700 units total 1
Lantus SoloStar pen capacity:
- Each pen contains 300 units of insulin glargine 100 units/mL 1
Number of pens needed:
- 2,700 units ÷ 300 units per pen = 9 pens required
- However, the prescription states "Dispense: 60" which appears to be an error
Critical Prescribing Issue
This prescription contains a significant dosing error that requires immediate clarification with the prescriber 2, 3:
- Lantus (insulin glargine) is a long-acting basal insulin designed for once-daily administration, not twice daily 4, 5, 6, 7
- The pharmacokinetic profile provides a relatively constant basal level for approximately 24 hours without pronounced peaks 4, 6, 7
- Administering Lantus twice daily at these doses (total 90 units/day) suggests either a prescribing error or an unusual clinical scenario requiring verification 5, 8
The standard approach would be:
- Single daily dose of basal insulin (typically 40-60% of total daily dose if on basal-bolus regimen) 2
- If 90 units total daily dose is appropriate, this should typically be given as one injection, not split 5, 6
Before dispensing, verify with prescriber:
- Whether twice-daily Lantus dosing is intentional (occasionally used in highly insulin-resistant patients) 5
- Whether rapid-acting insulin was intended instead of Lantus for the mealtime doses 2, 3
Correct Dispensing Quantity
If the prescription is verified as correct: dispense 9 pens (not 60 as written) to provide adequate supply for the 2,700 units needed over 30 days 1.