5.1 High-Alert Pharmacology, Reversal Antidotes & IV Safety
Master high-alert medications (insulin, heparin, warfarin, digoxin, opioids, potassium), clinical antidotes, and vesicant extravasation.
🎯 Key NCLEX-RN® Clinical Takeaways
- In DKA, NEVER start IV insulin if serum potassium is < 3.3 mEq/L; insulin drives potassium into cells, causing fatal cardiac arrest.
- Heparin antidote: Protamine Sulfate (target aPTT 1.5-2.5x control); Warfarin antidote: Vitamin K / PCC (target INR 2.0-3.0 or 2.5-3.5).
- Digoxin toxicity is potentiated by hypokalemia; signs include yellow-green halos and bradycardia; Antidote is Digibind.
- NEVER give potassium chloride IV push (causes fatal asystole); peripheral IV rate must not exceed 10 mEq/hour.
- Opioid reversal: Naloxone has a shorter half-life than opioids; monitor for recurrent respiratory depression when naloxone clears.
High-alert medications bear heightened risk of causing significant patient harm when used in error. Insulin and potassium require independent double-checks prior to administration.
Anticoagulation management requires strict lab surveillance: aPTT for heparin and INR for warfarin. Reversal agents must be immediately accessible: protamine sulfate for heparin, vitamin K for warfarin, and naloxone for opioids.
Extravasation of vesicant vasopressors (norepinephrine, dopamine) causes localized ischemic necrosis. The infusion must be stopped immediately, drug aspirated, and phentolamine infiltrated locally to reverse alpha-1 vasoconstriction.
⚠️ Common Pearson VUE / NCLEX Traps
- Giving IV insulin in DKA when potassium is low, triggering instant hypokalemic cardiac arrest.
- Administering potassium chloride via free-flow gravity tubing or via rapid IV push.
Knowledge Checkpoint
A 22-year-old client presents in diabetic ketoacidosis (DKA) with blood glucose 580 mg/dL, arterial pH 7.18, serum bicarbonate 10 mEq/L, and serum potassium of 3.1 mEq/L. The emergency physician orders a bolus of IV regular insulin 0.1 units/kg followed by a continuous infusion of 0.1 units/kg/hour. What is the nurse's priority action before administering the insulin?