December 17, 2003
Blood Tests and Insulin Injections
Question from South Fulton, Tennessee, USA:
My son was diagnosed with type 1 diabetes 6 months ago, and we are doing very well keeping his sugars in control. The problem is the insulin. I have heard that the insulin is good for about a month, and then it starts to loose its potency and needs to be discarded. My son is using only 6-8 units of Humalog a day. My doctor prescribed Humalog 1.5ml cartridges - we use needles not a pen! This was working wonderful, but then the bottles started busting after about 5 or 6 uses. Any suggestions? We have private insurance, so we pay for our prescriptions up front, and are reimbursed later (usually 6-8 weeks later). Thank you so much for your help.
I expect they are not injecting air and the vial is imploding rather than exploding. I didn’t realize you could get enough vacuum on the tube to break it. I also haven’t tried to burst one injecting too much air. My patients never complain of this. I instruct them to pretend it is a 1000 unit vial. Do it exactly as a vial. Inject air and take out insulin, unit for unit.
Additional comments from Dr. David Schwartz:
I concur that this sounds like a physics issue! I’d suggest that they work with a CDE to review their technique.
Additional comments from Barb Schreiner, diabetes nurse specialist:
This does sound like too much pressure in the pen cartridge. Try only putting air into the cartridge when it becomes more difficult to pull out a dose.