How do I switch a patient from intravenous (IV) insulin to subcutaneous (subcut) insulin?

From the Guidelines

To switch a patient from IV to subcutaneous insulin, administer the first dose of subcutaneous basal insulin 2 hours before discontinuing the IV insulin infusion, with the dose of basal insulin calculated as 60-80% of the daily infusion dose, as recommended by the most recent guidelines 1. When transitioning from intravenous to subcutaneous insulin, it is crucial to follow a protocol that minimizes morbidity and costs of care. The key steps involve:

• Calculating the total daily insulin requirement based on the patient's insulin usage over the past 6-8 hours and extrapolating to 24 hours.
• Dividing the total daily insulin requirement into basal and bolus components, with basal insulin (such as glargine or detemir) making up 60-80% of the daily infusion dose, as suggested by 1.
• Administering the first dose of subcutaneous basal insulin 2 hours before discontinuing the IV insulin infusion to ensure adequate overlap and prevent hyperglycemia during the transition.
• Monitoring blood glucose closely during and after the transition, typically checking levels before meals and at bedtime, and adjusting the insulin regimen as needed. This approach is supported by the most recent guidelines, which emphasize the importance of a structured transition protocol to minimize complications and ensure optimal glycemic control 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Switching from IV Insulin to Subcutaneous Insulin

To switch a patient from intravenous (IV) insulin to subcutaneous (subcut) insulin, several factors need to be considered, including the patient's current IV insulin requirements, their nutritional status, and any comorbid conditions.

• The optimal initial dose of subcutaneous insulin after IV infusion is controversial, but studies suggest that estimating the initial dose as 50% of the daily IV insulin requirements may be adequate for patients on enteral nutrition (EN) 2.
• However, for patients on total parenteral nutrition (TPN), this initial dose may be inadequate, and a higher dose may be required to achieve target blood glucose levels 2.
• A retrospective study found that transitioning critically ill adults to 50-59% of their 24-hour IV insulin requirements resulted in the highest rate of blood glucose concentrations within the target range (68%) 3.
• Another study found that converting patients from continuous insulin infusion to subcutaneously administered insulin glargine at a dose equal to 80% of the total daily insulin requirements resulted in the highest percentage of blood glucose values within the target range of 80-150 mg/dL 4.

Considerations for Transition

When transitioning a patient from IV to subcutaneous insulin, it is essential to consider the following factors:

• The patient's nutritional status, including whether they are receiving enteral or parenteral nutrition 2, 3.
• The type of subcutaneous insulin to be used, such as insulin glargine or detemir 4, 5.
• The use of institutional and computerized protocols to guide the transition process 6.
• The need for ongoing blood glucose monitoring and adjustments to the subcutaneous insulin dose as needed.

Clinical Situations

The transition from IV to subcutaneous insulin may need to be tailored to specific clinical situations, such as:

• Patients previously on insulin pumps 6.
• Patients requiring glucocorticoids and enteral tube feedings 6.
• Patients with type 1 diabetes or end-stage renal disease, for whom further research is needed to guide transition management 6.