A form of insulin that is five times as concentrated as standard U-100 insulin. U-500 insulin is commonly used to treat people with severe insulin resistance (sometimes defined as people who require more than 200 units of insulin per day). Insulin resistance is a condition in which the body doesn’t use insulin efficiently and needs large amounts of it to function effectively. Extreme insulin resistance is most commonly caused by gross obesity (defined as weighing more than twice a person’s ideal weight or being more than 100 pounds overweight), but may also be caused by endocrine diseases such as Cushing syndrome, genetic abnormalities in the insulin receptors, and antibodies against the insulin receptors.
The larger the volume of insulin that is injected, the less predictably it is absorbed, and the less predictable its blood-glucose lowering effects. Since a dose of U-500 insulin takes up only one-fifth of the volume of the same dose of U-100 insulin, there is less variation in absorption from one day to the next, or from one body region to another. U-500 insulin can be especially helpful for people who need large doses of insulin but don’t have much fat under the skin. Another benefit of U-500 insulin is that it is less expensive, with a lower cost per unit than other types of insulin.
In treatment guidelines proposed by the National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK), anyone requiring 200 units or more of insulin per day should be treated with U-500 exclusively: Those requiring 200–300 units a day should get two injections, those requiring 300–750 units a day should get three injections, those requiring 750–2,000 units a day should get four injections, and those requiring over 2,000 units a day should be considered for an insulin pump that infuses U-500 insulin. A study reported in the journal Diabetes Care showed that switching obese, markedly insulin-resistant people with Type 2 diabetes to U-500 insulin resulted in a decrease of 2.5% in HbA1c (or A1C) level, meaning that their blood glucose control improved significantly.
To read more about insulin resistance, go to www.diabetesselfmanagement.com/2/resistance.