Continuous intravenous (IV) infusion using Humulin R (insulin human) 100 units/mL (U-100R) is a method of insulin delivery specifically for use in hospitalized patients.1-3

For IV use, U-100R may be administered only under medical supervision with close monitoring of blood glucose (BG) and potassium levels to reduce the risk of hypoglycemia and hypokalemia.4

When administered intravenously in doses ranging from 0.1 to 0.2 units/kg, the pharmacologic effect of U-100R

• begins approximately 10 to 15 minutes after administration, and
• ends at a median of approximately 4 hours (range: 2-6 hours) after administration.4

Typically, IV insulin infusions are mixed to a concentration of 1 unit/mL in normal saline and infused into a dedicated IV line. If the patient requires volume restriction, a more concentrated solution may be used.2

Infusion bags prepared with U-100R are stable when

• used at concentrations from 0.1 unit/mL to 1 unit/mL containing 0.9% sodium chloride, and
• stored in a refrigerator (2°C to 8°C) for 48 hours and then may be used at room temperature for up to an additional 48 hours.4

The priming of IV sets to accommodate the adsorption of insulin is included in several institutional protocols.5-7

A study designed to quantify the insulin adsorption losses to IV lines

• added 100 units of Regular Human Insulin to each of 20 polyvinyl chloride bags containing 100 mL of 0.9% sodium chloride for injection
• delivered the resultant solutions (1 unit/mL) through standard polypropylene infusion sets, and
• collected samples at 10-mL intervals from 0 to 50 mL.7

The authors concluded that, for standard IV insulin infusions, a priming volume of 20 mL was sufficient to minimize the effect of insulin adsorption losses to IV lines.7