Converting from Insulin Infusion to Subcutaneous Insulin

Introduction to Conversion

The American Diabetes Association recommends calculating 60-80% of the total daily insulin requirement from the IV infusion and administering this as subcutaneous insulin in a split dose regimen, typically with 2/3 in the morning and 1/3 in the evening 1, 2

Calculate the total daily insulin requirement based on the average hourly rate during the final 6-12 hours of the IV insulin infusion, then multiply the hourly rate by 24 to get the estimated total daily requirement, for example, if average IV insulin rate is 1.5 units/hour, the estimated 24-hour requirement would be 36 units 1, 2
Convert to 60-80% of the calculated total daily requirement, with this reduction accounting for differences in bioavailability between IV and subcutaneous administration 1, 2, 3
Divide the total subcutaneous insulin dose into two daily injections, typically using a morning:evening ratio of approximately 2:1 (or 60:40 to 70:30), for example, if total daily dose is 30 units, give 20 units in morning and 10 units in evening 4, 5

Administer first dose of subcutaneous insulin 2-4 hours before discontinuing the IV insulin infusion, with this overlap ensuring adequate insulin coverage during the transition period 1, 3, 6
Adjust doses based on pre-meal glucose patterns, and for hypoglycemia, determine cause; if no clear reason, lower corresponding dose by 10-20% 4, 5
Be aware that premixed insulin formulations have been associated with higher rates of hypoglycemia in hospitalized patients compared to basal-bolus regimens, and consider individual patient factors such as meal patterns, renal function, and risk of hypoglycemia 2, 3, 7, 8

Avoid prolonged use of sliding scale insulin alone as the sole treatment strategy, and do not use the same insulin dose calculation for all patients without considering individual factors 1, 2, 3, 8
Be cautious with evening doses as nocturnal hypoglycemia risk is higher 3, 7