June 22, 2010

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!


Unknown said...

you must have meant to write a Frio pack, not a Frigo pack
Nice post, scary.

Rabbi Hirsch Meisels

Michael Barker said...

I just tossed some Levemir because I was suspicious of it.
I too wondered what might have happened to it before it got to me. What nettles me is that there is no way to test our supplies. I once had a small lab and all reagents were regularly tested. Some had indicators right on their vials. There should be a simple test for our supplies.

Only thing I could see doing is ordering your supplies in the spring or fall when temps are moderate.

Jenny said...

Rabbi Hirsch, You were correct. I fixed it.

Helen said...

My meter fritzed out this week. Maybe it was the heat. Not as big an issue as insulin, though.

Jenny said...

Someone who contacted me privately asked me to point out that the butter compartment of your fridge can be the worst place to store your insulin.

Besides the issue that the door compartment can be warmer than the fridge, the heavy doors of newer fridges are filled with shelves full of heavy things that vibrate when you close them. That vibration can also cause insulin to deteriorate.

Michael Barker said...

Vibration? Insulin is sensitive to this? Here is the problem refrigeration units have a motor which runs the compressor. It is the nature of such equipment to vibrate. You could damp this by bubble wrap around your supplies.

Jenny said...

I'm thinking more of the kind of vibration where the door visibly shakes because of milk and wine bottles and fifteen bottles of salad dressing moving in the shelf.

I don't know that the subtle vibration of a refrigerator is in the same realm.

ItsTheWooo said...

This is a very important post for patients jenny, thank you.

As a nurse, we all know insulin must be refridgerated... however, it isn't uncommon for them to sometimes be left in a medication cart for several hours where they reach room temp. I observed that as the insulin vial reaches mid way, or the end, it becomes less potent for many patients. Meaning to say, the patient will start to have higher blood sugars or unstable blood sugars (lows and highs).

I always try to refrigerate the insulins after use, so that they get a chance to cool up again for the next shift. But yea, it's a big issue. Most nurses don't realize it's important. Or doctors. Or pharmacists.

Jenny - are you sure vibration can cause insulin to deteriorate? We are taught in nursing school to shake insulin to ensure potency/even distribution of medication.

Michael - many glucometers come with control solutions that will tell you if your meter is in range... but as for insulin, there isn't a way to know. If your sugars start going up and you aren't sick/stressed/sleeping less it might be medications.

Lili said...

I've definitely had this problem after picking up insulin. Luckily my pharmacist knows me (always recommend this), so I was able to return it. The pharmacy techs, on the other hand, didn't seem to be aware of any issue with leaving insulin out of the fridge because "it's a 30 day supply." I had to ask them, "what if the patient isn't opening the insulin today? Then it's no longer a 30 day supply" before they got it.

I've also noticed when it's warm that some vials go bad a lot faster than others, and that's using an ice pack.

My insurance keeps trying to get me to use mail order, but I refuse. My roommate is forced to get his insulin by mail order in a 3 month supply, and he's had it arrive hot to the touch before. It took him a month to get it replaced. No, thanks.

Unknown said...

Thanks for your post. I din't know about this until i read it from here and i think it's safe to assume that doctors and pharmacist don't know about this either.Better stock up fair amount of vials and always monitor their storage container. Diabetes is an traitor kind of disease so better be ready anytime.