Regular insulin

Insulin must be administered via the parenteral route, usually the subcutaneous (SC) route Insulin cannot be administered orally because it is a protein and readily destroyed in the gastrointestinal tract. Regular insulin is the only insulin preparation given intravenously (IV). Regular insulin is given 30 to 60 minutes before a meal to achieve optimal results. 

When regular insulin and another insulin are mixed in the same syringe, the nurse must administer the insulin within 5 minutes of withdrawing the two insulins from the two vials. 

METHODS OF ADMINISTERING INSULIN. Several methods can be used to administer insulin. The most common method is the use of a needle and syringe Use of microfine needles has reduced the discomfort associated with an injection. Another method is the jet injection system, which uses pressure to deliver a fine stream of insulin below the skin. Another method uses a disposable needle and special syringe The syringe uses a cartridge that is prefilled with a specific type of insulin (eg, regular human insulin, isophane [NPH] insulin, or a mixture of isophane and regular insulin). 

A patient is prescribed 40 units NPH insulin mixed with 5 units of regular insulin. What is the total insulin dosage Draw a line on the syringe below showing the total insulin dosage. Describe how you would prepare the insulins. 

Metformin 1 000 mg orally twice daily Hydrochlorothiazide 25 mg orally once daily Nifedipine XL 60 mg orally once daily Regular insulin 4 units SC 3 times daily with meals Insulin glargine 20 units SC at bedtime... 

Regular insulin 10 units in the morning and 10 units in the evening... 

Patients with acute hyperkalemia usually require other therapies to manage hyperkalemia until dialysis can be initiated. Patients who present with cardiac abnormalities caused by hyperkalemia should receive calcium gluconate or chloride (1 g intravenously) to reverse the cardiac effects. Temporary measures can be employed to shift extracellular potassium into the intracellular compartment to stabilize cellular membrane effects of excessive serum potassium levels. Such measures include the use of regular insulin (5 to 10 units intravenously) and dextrose (5% to 50% intravenously), or nebulized albuterol (10 to 20 mg). Sodium bicarbonate should not be used to shift extracellular potassium intracellularly in patients with CKD unless severe metabolic acidosis (pH less than 7.2) is present. These measures will decrease serum potassium levels within 30 to 60 minutes after treatment, but potassium must still be removed from the body. Shifting potassium to the intracellular compartment, however, decreases potassium removal by dialysis. Often, multiple dialysis sessions are required to remove potassium that is redistributed from the intracellular space back into the serum. 

Dextrose and insulin (with or without sodium bicarbonate) are typically given at the time of calcium therapy in order to redistribute potassium into the intracellular space. Dextrose 50% (25 g in 50 mL) can be given by slow IV push over 5 minutes or dextrose 10% with 20 units of regular insulin can be given by continuous TV infusion over 1 to 2 hours. The onset of action for this combination is 30 minutes and the duration of clinical effects... 

Regular insulin is unmodified crystalline insulin commonly referred to as natural insulin. It is a clear solution that has a relatively rapid onset and short duration of action. On subcutaneous injection, regular insulin forms small aggregates called hexamers that undergo conversion to dimers followed by monomers before systemic absorption can occur. Therefore, patients should be counseled to inject regular insulin subcutaneously 30 minutes prior to consuming a meal. Regular insulin is the only insulin that can be administered intravenously. 

Three rapid-acting insulins have been approved in the United States lispro, aspart, and glulisine. Substitution of one or two amino acids in regular insulin results in the unique pharmacokinetic properties characteristic of these agents. Onset of action of rapid-acting insulins varies from 15 to 30 minutes, with peak effects occurring 1 to 2 hours following administration. 

NPH insulin can be mixed with regular insulin and used immediately or stored for future use up to 1 month at room temperature or 3 months in refrigeration. NPH insulin can be mixed with either aspart or lispro insulins, but it must be injected immediately after mixing. Whenever mixing insulin products with NPH insulin, the shorter-acting insulin should be drawn into the syringe first. 

A number of combination insulin products are available commercially. NPH is available in combinations of 70/30 and 50/50 with regular insulin. Two short-acting insulin analog mixtures are also available. Humalog Mix 75/25 contains 75% insulin lispro protamine suspension and 25% insulin lispro. Novolog Mix 70/30 contains 70% insulin aspart protamine suspension and 30% insulin aspart. The lispro and aspart insulin protamine suspensions were developed specifically for these mixture products and will not be commercially available separately. 

Administer regular insulin IV (0.1 units/kg) or IM (0.4 units/kg), then 0.1 units/kg per hour by continuous IV infusion increase 2- to 10-fold if no response by 2-4 hours. If initial serum potassium is less than 3.3 mmol/L (3.3 mEq/L), do not administer insulin until the potassium is corrected to greater than... 

Thereafter, the preceding parameters and other nutritional parameters should be monitored routinely or as indicated (Table 97-8). Random capillary blood glucose concentrations also should be monitored every 6 to 8 hours when initiating PN, and regular insulin should be administered to control glucose as needed (either by intermittent administration per sliding scale or as a continuous infusion). 

Regular insulin has a relatively slow onset of action when given subcutaneously, requiring injection 30 minutes prior to meals to achieve optimal postprandial glucose control and to prevent delayed postmeal hypoglycemia. 

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