regular insulin (human insulin)
Brand: Humulin R, Novolin R
ISMP High Alert Prototype: insulin-glargine
Drug Class: insulin
Drug Family: insulin
Subclass: short-acting (regular) insulin
Organ Systems: endocrine
Mechanism of Action
Unmodified human insulin that activates insulin receptors on muscle, adipose, and liver cells, promoting glucose uptake via GLUT4 translocation, glycogen synthesis, lipogenesis, and protein synthesis while inhibiting gluconeogenesis, glycogenolysis, and lipolysis.
insulin receptor (IR)
Indications
- type 1 diabetes mellitus
- type 2 diabetes mellitus (mealtime coverage)
- diabetic ketoacidosis (IV infusion)
- hyperkalemia (with dextrose)
- total parenteral nutrition (insulin supplementation)
- critical illness hyperglycemia
Contraindications
- hypoglycemia
- hypersensitivity
Adverse Effects
Common
- hypoglycemia
- weight gain
- hypokalemia (IV use)
Serious
- severe hypoglycemia
- hypokalemia (with IV administration)
- anaphylaxis
Pharmacokinetics (ADME)
| Absorption | subcutaneous (SC) or intravenous (IV) |
| Distribution | minimal protein binding |
| Metabolism | proteolytic degradation by insulinase |
| Excretion | renal filtration of metabolites |
| Half-life | 5–6 minutes (IV); SC variable |
| Onset | 30–60 minutes (SC); 10–30 minutes (IM); immediate (IV) |
| Peak | 2–4 hours (SC) |
| Duration | 5–7 hours (SC) |
| Protein Binding | minimal |
| Vd | 0.26 L/kg |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| beta-blockers | mask tachycardia; prolong hypoglycemia | moderate |
| corticosteroids, thiazides | increase insulin resistance; higher doses needed | moderate |
Nursing Considerations
- For SC use, administer 30 minutes before meals to coordinate peak action with postprandial glucose rise.
- For IV insulin infusion in DKA or hyperglycemia: use ONLY regular insulin; check glucose every hour; monitor for hypokalemia (add potassium to IV fluid as needed).
- Regular insulin can be given IV and is the insulin of choice for IV infusion protocols; rapid-acting analogs (lispro, aspart) should NOT be given IV.
- When mixing regular insulin with NPH: draw regular insulin first; contamination of regular vial with NPH alters pharmacokinetics.
Clinical Pearls
- Regular insulin remains the only insulin approved for IV infusion, making it the standard choice for DKA management protocols and insulin drips in the ICU.
- The combination of regular insulin plus dextrose is used to shift potassium intracellularly in hyperkalemia emergencies — a life-saving non-antihypertensive use of insulin.
Safety Profile
Pregnancy use-with-caution
Lactation safe
Renal Adjustment Required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.