Insulin Storage and Mixing
Storing Insulin
To protect your insulin's effectiveness, store unopened vials or cartridges in the refrigerator.1 The expiration period for opened insulin depends on the type of insulin. Check the package insert for instructions on storage and expiration time for unopened and opened insulin.
Avoid exposing your current insulin vial or pen to excess agitation or extreme temperatures—generally speaking, it should be kept between 36 and 86 degrees Fahrenheit.1 An insulated bag will help you keep your supplies together and your medication in a safe range. Never store insulin in the freezer, direct sunlight or the glove compartment of your car.2
Mixing Types of Insulin Together
Your healthcare team may recommend mixing short- and intermediate-acting insulins in one syringe to get a personalized effect.1 In addition, there are pre-mixed insulins, which can be helpful for people who have difficulty mixing insulin or whose diabetes has been stabilized on a specific combination.
Some insulins should not be mixed, or mixed only at the last moment, because the chemical structure can change and lead to unpredictable results. Only mix insulin on your doctor's advice, or ask your doctor if a pre-mixed insulin might be right for you.1
Inspect Before You Inject
Rapid-acting, regular and glargine (Lantus) insulins look clear in the vial. Because intermediate, lente and ultralente insulins use additional ingredients to slow their absorption, they have a cloudy, milky appearance. They need to be mixed by gently rolling the vial or pen between your hands. Any time your insulin doesn't look the way it should, don't use it.1
Before using any insulin, take a close look. Clumping, frosting, crystals, discoloration or other visible changes can be a sign that your insulin is no longer effective.1 Don't take chances. Start with a new vial.
1 American Diabetes Association. "Insulin Administration." Diabetes Care 27:S106-S107, 2004. Available at: http://care.diabetesjournals.org/cgi/content/full/27/suppl_1/s106?maxtoshow=&HITS=10&hits=10& RESULTFORMAT=&fulltext=insulin+administration&andorexactfulltext=and&searchid=1&FIRSTINDEX=0 &sortspec=relevance&resourcetype=HWCIT. Accessed November 7, 2007.
2 American Diabetes Association. "Insulin Storage and Syringe Safety Information." Available at: http://www.diabetes.org/type-1-diabetes/safety.jsp. Accessed November 7, 2007.