A recent review that included 4 published studies of intravenous insulin vs. rapid acting subcutaneous insulin in patients with diabetic ketoacidosis (DKA) demonstrated that either route is safe and equally efficacious. All the studies excluded complicated presentations such as patients with organ dysfunction. The adult studies showed no statistical difference between the 2 groups in their time to resolution of ketoacidosis (approx 12 hours), the amount of insulin required, and number of hypoglycemic episodes. The included pediatric study had similar resolution of ketosis in both groups although the subcutaneous group had a slightly longer time to resolution of acidosis. The use of subcutaneous insulin can possibly avoid an admission to the ICU for management of DKA leading to lower hospital cost.
Pharmacokinetics of insulin
- Subcutaneous regular insulin has an onset of 1 hour, peak of 1-5 hours, and duration of action of 6- 10 hours.
- Intravenous regular insulin has an onset of minutes and a half life of 9 minutes.
- Rapid acting insulin (lispro, aspart) have an onset of 10-20 minutes, peak of 30-90 minutes, and duration of action of 3-4 hours.
Dosing used for subcutaneous insulin in diabetic ketoacidosis
- lispro: 0.3 U/kg bolus followed by hourly injections of 0.1 U/kg
- aspart: 0.3 U/kg bolus, followed by hourly injections of 0.1 U/kg, and then reduced to 0.05 U/kg when glucose reaches 250
- aspart: 0.3 U/kg bolus, followed by injections of 0.2 U/kg every 2 hours, and then reduced to 0.1 U/kg when glucose reaches 250
Mazer M, Chen E. Is subcutaneous administration of rapid-acting insulin as effective as intravenous insulin for treating diabetic ketoacidosis. Ann Emerg Med. 2009 Feb;53(2):259-63.
Umpierrez GE, et al. Efficacy of subcutaneous insulin lispro versus continuous intravenous regular insulin for the treatment of patients with diabetic ketoacidosis. Am J Med. 2004 Sep 1;117(5):291-6.