Letter to the Editor: A Practical Guide to Concentrated Insulin for Pharmacists

摘要

We would like to respond to the insightful review by Andres and Clements that provides a detailed guide for the use of concentrated insulin, U-500 human regular insulin (U-500R), for pharmacists.Andres and Clements describe U-500R as being 5 times more potent than U-100 human regular insulin (U-100R). In the updated package insert (March 2013), U-500R is described as 5 times more concentrated than U-100R. This means that there are 500 units in 1 mL of U-500R and 100 units in 1 mL of U-100R. There is no difference in units between both types of insulin. Accordingly, "a unit is a unit" meaning an equipotent unit of U-500R is delivered in one-fifth the volume than those of U-100 insulins. This has been frequently misstated even in expert commentaries and is crucial for pharmacists and prescribers to understand. To be completely unambiguous, the prescribed dose of U-500R should always be expressed in the actual units of insulin and the syringe markings to be administered in accordance with the syringe type to be used.