• image.alt
  • With Mayo Clinic diabetes educators

    Nancy Klobassa, R.N., and Peggy Moreland, R.N.

    read biography

Mayo Clinic Health Manager

Get free personalized health guidance for you and your family.

Get Started

Free

E-Newsletter

Subscribe to receive the latest updates on health topics. About our newsletters

  • Housecall
  • Alzheimer's caregiving
  • Living with cancer

  • Living with diabetes blog

  • May 30, 2009

    Blog: Beware summer extremes with insulin

    By Nancy Klobassa, R.N., and Peggy Moreland, R.N.

7 comments posted

Hi everyone.

This week I'd like to talk about how to manage insulin storage in the extreme temperatures of summer. In upcoming weeks, I'll focus on the proper maintenance of meters, testing supplies and other supplies in extreme temperatures and altitudes.

A number of years ago, I met with a client who used a rapid insulin pen for meal dosing. She shared this story:

She attended the county fair on an exceptionally hot day, and had placed her insulin pen in the back pocket of tight jeans and walked around the fairgrounds all day. She used the pen for covering meals eaten at the fair, and her blood sugars were running higher than normal, but she related this to all the junk food. The next day her blood sugars continued to run high and when she took her (rapid) insulin, it didn't seem to affect her blood sugar level at all; in fact, it was like she was taking water instead of insulin. She wondered if the heat had affected her insulin, so she switched to a new insulin (disposable) pen, and soon after her blood sugars started to drop.

Has this or something similar happened to you?

I looked at insulin manufacturer's Web sites and found that for the majority of all types and brands of insulin, the maximum temperatures recommended are as follows:

  • Opened room temperature insulin should not exceed 86 degrees F (30 C) with the exception of Lantus, which should not exceed 77 degrees F (25 C).
  • Most manufacturers of insulin recommend discarding insulin if it exceeds 98.6 degrees F (37 C).

Other non insulin diabetic injectable medications:

  • Glucagon and Byetta should not exceed 77 degrees F (25 C).
  • Symlin should not exceed 86 degrees F (30 C).

Avoiding potential problems

  • Temperatures exceeding manufacturer's recommendations for insulin/medications

Store your insulin in the refrigerator, in an insulated case or cooler with a freezable gel pack, or use a cooling wallet. Cooling wallets are available through many diabetes supply companies and keep insulin vials, pens and pumps cool at a safe temperature without the need for refrigeration or ice. The wallets have a liner filled with crystals. The liner is immersed in cold water for 10-15 minutes, and placed back into the wallet, along with the insulin. It works by relying on the process of evaporation for cooling, can keep insulin cool for up to 48 hours, and is reusable.

Remember, after opening a vial of insulin or starting a new insulin pen, the insulin loses its potency and should be thrown away after so many days, depending on the manufacturer's guidelines. Generally, most vials of insulin are good for 28 days after opening with the exception of Levemir (detemir), which is good for 42 days. Other pens are good for 10, 14, 28 or 42 days. Check the medication insert.

  • Avoid temperature extremes

Never freeze insulin or expose it to extremely hot temperatures or direct sunlight. Never leave it in your car. Never place it directly on ice or an ice pack.

  • Watch for changes in insulin appearance

Throw away insulin that is discolored or contains solid particles.

What about insulin pumps?

Heat can make proteins like insulin harden, which increases the potential for infusion set occlusions (blockage). If you live in a hot climate and especially if you work outdoors, you may need to pay closer attention to how the heat can affect your insulin. A patient of mine, who is a roofer in Arizona, found that he needed to replace the insulin in his pump reservoir daily to avoid having high blood glucose readings. Using a pump wallet could be another option for people concerned about the effects of heat on their insulin. Also, make sure that the infusion set tubing is tucked in your clothing and not hanging out and exposed to the light and or heat.

Please share your stories.

Have a great week,

Nancy

7 comments posted

blog index

  • August 22, 2009 9:02 a.m.

    what should be your ideal glucose reading after being on insulin?

    - charles

  • July 23, 2009 3:50 p.m.

    Ginette. It sounds like you need your insulin dose adjusted to cover your higher blood glucose readings. Also, you should see a diabetes educator to learn how to adjust your insulin doses based on blood glucose patterns and learn carb counting so you can use an insulin to carb ratio to cover food. This insulin to carb ratio can be figured out by your healthcare provider. This will give you more flexibiliy in your program.

    - Nancy and Peggy

  • July 18, 2009 11:27 a.m.

    I have been on Lantus (24 units) for now 4 years. My A1C climbed to 7.0 and my doctor put me on fast acting Apidra but only gave me a general guideline of "start with 3 units and go from there". Is there a formula by which I can determine how much Apidra to inject in relation to my pre-meal blood sugar reading, the number of carbs I am about to eat and the number of units of Apidra I should use????

    - Ginette B.

  • June 18, 2009 1:47 p.m.

    Starting insulin: your healthcare provider will help you determine when its necessary to start insulin. Individuals with type 1 diabetes have no choice but to be on insulin injections, since their bodies make minimal or no insulin of their own.

    - Nancy and Peggy

  • June 12, 2009 1:34 a.m.

    how do you know if you need insulin?

    - christe

  • June 4, 2009 3:59 p.m.

    Hi Gail, if you think your insulin or Byetta may have been exposed to extreme temps, about the only way to know this is to switch to a new pen and if your numbers are much better then it is probably the cause.

    - Nancy and Peggy

  • June 2, 2009 1:53 p.m.

    i take both lantus insulin pen and byetta pen. The insulin pen is 50mg at bedtime. The Byetta is twice a day once at breakfast and once at supper (10Mg ea) The past few days my sugar reading is out of control........the expiration date is fine on both .....what should I do.........Could one of these have gone bad?

    - gail napolitano

Post a comment

Text Size: smaller largerlarger