My 14 year old daughter is currently using Humalog as part of her insulin regimen. The doctor says that we must replace the vial every 30 days, whether it is empty or not. She does not even use half the vial in 30 days and it seems wasteful to throw it out. Is this true? Why is this not the case with the Regular and NPH she is taking?

The newer insulins go “bad”. Actually, the older ones did, too, we just didn’t seem to manage diabetes as well with them and either didn’t notice or thought it was the patient not taking good care.

Anyway, throw it out. It does lose potency.

LD
Additional comments from Dr. David Schwartz:

I’d change out month old NPH and Regular, too.

If you don’t want to “waste” as much, you might consider getting insulin in pen cartridges and use the cartridges in pens or as smaller vials.

A vial of insulin holds 10 mL. A cartridge holds about 3 mL. I believe that the cartridges of 5 to-a-box cost similarly to a vial. Ask your pharmacist.

DS

[Editor’s comment: Please see Eli Lilly’s How do I store my insulin? on their web site.

BH]