Heat Harms Insulin, Meters, and Even Some Oral Drugs!

A recent article in Science Daily reports on a presentation given at this week's meeting of the Endocrine Society.

It's worth a look: Science Daily: Many People with Diabetes Do Not Know or Heed Dangers of Hot Weather

Unfortunately, while the points it makes are true, a much better title would have been Many doctors and pharmacies don't know or heed the dangers of hot weather.

Just this week I heard from someone whose insurance forces him to get his medications from a mail order service that refuses to ship insulin overnight or with any protection against temperature. This, even though the insulin manufacturer documented for this person that when insulin sits in a hot truck it dies.

Meters and test strips can also become unusable if left in a hot car. I've cooked a whole vial of strips by leaving them on a car seat when it was in the 90s outside.

The Science Daily article points out that even pills can be ruined by heat. That was new to me but I am no stranger to the phenomenon where one month's Metformin works a whole lot better than another's. Sadly, I am also no stranger to the phenomenon where when you complain to a pharmacy that your insulin is weak or there seems to be something wrong with your pills, they assure you it couldn't possibly be true and that no one else has complained about them.

No one else probably has complained, because they probably assumed it was something in their own physiology that made their blood sugars suddenly shoot up. Given the vague way that most people with Type 2 are prescribed insulin and their lack of understanding of how insulin doses should correlate tightly with blood sugars, it is no surprise that customers pay for their insulin and accept whatever they're given, even if it barely works.

Sadly, the problems caused by temperature are not limited to heat. I took an insulin pen with me, in my purse, when I dined at a restaurant last December when outside temperatures dropped to a low in the very low 20s. Even though I was only outside for maybe ten minutes, that was enough to freeze the pen. A faulty fridge can do the same thing. If you see ice crystals in your milk or vegetables, chances are any insulin you had in the fridge is toast, too.

But just try getting a replacement from your health insurance when your insulin pen dies. Good luck!

Because pharmacies get their insulin from wholesalers who won't ship it overnight or with temperature buffering anymore, there is no easy solution to this problem. The insulin you buy from the pharmacies is just as likely to have sat in a hot truck for three days as the mail order stuff.

Doctors aren't aware of this problem, and neither, based on my experience, are pharmacists. That means if you suddenly see unexplained high blood sugars after using a vial of bad insulin, the doctor may just raise your dose rather than insist that your pharmacy replace the vial.

What makes it more of a problem is that this issue is fairly. Five years ago mail order pharmacies always shipped insulin overnight with cold packs. The switch to sending it in hot slow trucks is a recent, cost cutting move--one that is going to result in more blindness, amputation and death for those who use dead insulin and more hypos for those who get used to weakened insulin and then get a vial of full strength.

I wish I had some sage words of advice to offer about how to deal with this. About all I can do is assure you that if you are experiencing major fluctuations in blood sugar response from vial to vial or pen to pen it might not be your physiology at fault.

If you use small doses, it is also a good idea to remember that some insulins weaken over time no matter what you do. I found Levemir very prone to weaken. On the other hand when I used Apidra it stayed potent for many months even though it was not refrigerated. The Apidra I used was a sample my doctor gave me since my insurance wouldn't pay for it. When the doctor got another batch, mailed to her in the summer, it arrived dead. No insulin can survive temperatures in the very high 90s for very long.

If you have a good vial or pen, protect it from heat and cold. A Frio pack works well for this. Don't leave your meter in a hot or cold car, either. And remember that even ten minutes of exposure, as you walk to a restaurant on a very hot or very cold day may be enough to weaken your insulin or render it useless.

Post your experiences with this issue in the comments, along with any solutions you might have found!