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From Arizona, USA:

My dad is on a mail order prescription plan, and we live in Arizona so the temperatures are high in the summer. For about three months, his insulin was so hot when it was delivered that it was hard to hold in your hand. The pharmacist at the mail order place said it was okay to use even though it had gotten hot, so he did. Over the next few months, he became so ill we thought he was going to die. He had to increase his dosage. My mom is the one who thought of the insulin temperatures, and the doctor said it was worth a try to get fresh insulin. My dad did and started to improve in a few days.

Have you ever run across anything that explains what will happen to insulin if it is exposed to high temperatures (over 99 degrees)? I have read it will break down and the potency will decrease, and I know insulin starts to react at body temperatures. However, t I need to know if it is toxic if you use it for several months.

We would like insulin to be labeled now to really show people how bad it is to take insulin after it has been exposed to heat. I can find no place where it is revealed what will happen. We do not want someone else to go through what my dad did.


Insulin is only stable below 86 degrees F, and then only for 14 days. At higher temperatures it will denature at a rate that is a function of both time and temperature. The breakdown products are not toxic however so that I think that your father's problems were due to unwitting insufficient insulin administration.

The package insert with every bottle of insulin does make these temperature restrictions clear. If the pharmacist at the mail order source did indeed give you contrary information, he was incorrect.


[Editor's comment: The pharmacist was definitely wrong. Call back to the same phone number, and ask to speak to the pharmacist's supervisor. Then read this reply to the supervisor, and ask that he/she make sure that their staff are all aware of the fact that insulin must be kept at reasonable temperatures (below 86 degrees F and above freezing). If the supervisor isn't willing to listen, call the insurance company, and complain to them. If the insurance company isn't willing to do something, call the insurance commission in your state. As you are now aware, this is simply too important to have erroneous information being given out! WWQ]

Original posting 10 Aug 2001
Posted to Insulin


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Last Updated: Tuesday April 06, 2010 15:09:24
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