Even since I started using insulin post-transplant, I have been wondering how the pharmacy knows how many pens to send me. Each time I refill my prescription, they send different numer of boxes of pens. So, I finally looked at the small print on the actual pen.
For Toujeo, each pen contains 1.5 mL of solution and there are 300 units of insulin per milliliter. That means each pen has 450 units. Since each box has three pens and I use thirty-two units daily, the box should last me forty-two days. That is why the pharmacy sent me three boxes when my doctor gave me a 90-day prescription.
For Humalog, each pen holds 3 mL but the solution only contains 100 units per milliliter. Each pen only holds 300 units. My current prescription is a sliding scale, but the base dosage is 8/10/10 or twenty-eight units daily. Humalog comes in boxes of five pens, so each box is good for fifty-three and a half days. Instead of sending me two boxes, the pharmacy sent four boxes instead. Do they assume that I will end up using double the base prescription?
The result is that I have many boxes of insulin in my refrigerator. At lease now I can estimate how many days of insulin I have left when refilling my prescriptions.
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Ha! It says “Units per pen: 450” right on Toujeo’s website.
Life with chronic diseases 