Educational use only. Drug cards are AI-assisted study material for NCLEX preparation.

← All Drug Cards

Insulin (regular, NPH, lispro, aspart, glargine, detemir)

Antidiabetic — endogenous and analog insulins

Mechanism of action

Replaces or supplements endogenous insulin. Binds the insulin receptor, drives glucose into muscle and adipose cells, suppresses hepatic glucose output, and promotes potassium uptake into cells. Used for type 1 diabetes (always required), type 2 diabetes when oral agents are insufficient, hyperglycemic crises (DKA, HHS), and emergent hyperkalemia.

Adverse effects

Life-threatening / NCLEX-tested

  • Hypoglycemia — life-threatening; can cause seizures, coma, death
  • Severe hypokalemia (especially during DKA correction)
  • Anaphylaxis (rare)
  • Lipohypertrophy or lipoatrophy at injection sites with poor rotation
  • Weight gain

Side effects

Common — what to teach

  • Mild injection-site irritation
  • Mild edema with intensification
  • Sweating, tremor, hunger (early hypoglycemia)
  • Visual changes early in tight glucose control
  • Local rash

Food & drug interactions

Beta blockers MASK hypoglycemia tachycardia warning — rely on sweating, hunger, confusion. Alcohol increases hypoglycemia risk and prolongs duration. Steroids, thiazides, and atypical antipsychotics raise glucose and increase insulin requirements. Only Regular insulin can be given IV. NPH is the only insulin that's cloudy and must be rolled (never shaken). When mixing Regular + NPH, draw Regular FIRST ("clear before cloudy").

Nursing implications

Assessment, monitoring, patient teaching

  • Onset/peak/duration cheat-sheet — Lispro/aspart: onset 15 min, peak 1 h, duration 3–4 h. Regular: onset 30–60 min, peak 2–3 h, duration 5–8 h. NPH: onset 1–2 h, peak 4–12 h, duration 12–18 h. Glargine/detemir: onset 1–2 h, no real peak, duration ~24 h
  • When mixing in one syringe, draw clear Regular FIRST, then cloudy NPH — "clear before cloudy, RN before LPN"
  • Glargine and detemir CANNOT be mixed with any other insulin
  • Rotate injection sites within an anatomic area (abdomen preferred for fastest absorption); avoid bruising and scarring
  • Two-nurse independent verification for IV insulin doses and pediatric patients — high-alert medication
  • Always have rapid-acting glucose source nearby (15 g of fast carbs for conscious; D50 IV or glucagon IM for unconscious)
  • Hold or adjust for NPO patients; sliding-scale orders should specify hold parameters

When to hold / contraindications

  • Blood glucose below the order parameter (often < 70 or < 80 mg/dL)
  • Patient is NPO without provider direction (basal often continued, prandial held)
  • Severe hypokalemia (K+ < 3.3) — correct potassium first in DKA before insulin
  • Active hypoglycemia symptoms — treat first, do not give more insulin

Memory anchor

"Clear before cloudy" when mixing Reg + NPH. "15-15 rule" for hypoglycemia: 15 g fast carbs, recheck in 15 min. Only Regular goes IV. Glargine/detemir never mix.

Reminder: Drug cards are study aids, not clinical guidance. Always cross-check doses, holds, and contraindications with your facility's formulary and your clinical instructors before patient care.

Practice Insulin questions

Test your recall on real NCLEX-style pharmacology questions — with full rationales and an AI Coach for the parts you miss.

Start Free PracticePharmacology Questions