The concept of insulin stacking has been traditionally implied to short-acting insulin administration. In these vignettes, we introduce an equally important concept of stacking basal insulin when subsequent injections of basal insulin are given with the previously administered insulin is still on board. These 5 vignettes illustrate complexity of switching patients to and from degludec in both inpatient and outpatient situation. PK and PD of these insulins dictate the most reasonable course of action. Consideration of PK/PD of various insulins, while deciding on their dosing and timing, would prevent stacking basal insulins. For example, U300 glargine has a half-life of 19 hours and is less potent than U100 glargine on a unit-to-unit basis. Although not addressed in this article, it will certainly create its own challenges during transitions.
Our poll of endocrinologists revealed multiple approaches as well as elements of confusion among providers. Because there is more than 1 correct way of implementing these transitions, we urge our colleagues to institute a very close follow-up of these patients with frequent adjustments of insulin dose to avoid stacking with potential hypoglycemia.
The authors are grateful to all members of the PRIDE group participating in the survey.
J Clin Endocrinol Metab. 2020;105(6) © 2020 Endocrine Society