NCLEX-RN - Pharmacology & High-Alert Medications

• Mechanism: Decreases heart rate and myocardial contractility by blocking beta-adrenergic receptors.
• Assessment: Hold medication if apical pulse is $<60\text{ bpm}$ or systolic blood pressure (SBP) is $<90-100\text{ mmHg}$.
• Contraindication: Non-selective beta-blockers (e.g., Propranolol) are contraindicated in clients with asthma or COPD due to risk of beta-2 receptor blockade causing severe bronchospasm.

• Mechanism: Prevents conversion of Angiotensin I to Angiotensin II, causing vasodilation.
• Key Side Effects:
1. Dry Cough: Caused by bradykinin accumulation (non-harmful, but requires drug switch to ARB like Losartan).
2. Hyperkalemia: Monitor potassium levels ($>5.0\text{ mEq/L}$).
3. Angioedema: Rapid swelling of lips, tongue, and airway (Life-threatening! Priority: Maintain airway, discontinue drug, administer epinephrine).

• Therapeutic Range: $0.5-2.0\text{ ng/mL}$
• Toxicity Signs: Early signs include nausea, vomiting, anorexia, and abdominal pain. Late signs include visual disturbances (yellow-green halos, blurry vision) and bradycardia.
• Risk Factor: Hypokalemia ($<3.5\text{ mEq/L}$) significantly increases the risk of digoxin toxicity.
• Antidote: Digoxin immune Fab (Digibind).

• Monitoring Parameter: Prothrombin Time (PT) and International Normalized Ratio (INR).
• Target INR: $2.0-3.0$ for general indications (AFib, DVT); $2.5-3.5$ for mechanical heart valves.
• Antidote / Reversal: Vitamin K (Phytonadione); fresh frozen plasma (FFP) for emergency bleed.
• Client Teaching: Maintain consistent dietary intake of Vitamin K (green leafy vegetables); avoid sudden increases or decreases.

• Monitoring Parameter: Activated Partial Thromboplastin Time (aPTT).
• Target Therapeutic Range: $1.5-2.5\times$ baseline control value (typically $60-80\text{ seconds}$).
• Antidote / Reversal: Protamine Sulfate.
• Complication: Heparin-Induced Thrombocytopenia (HIT)—suspect if platelet count drops by $>50\%$ from baseline after starting heparin.

• Onset: $10-15\text{ minutes}$
• Peak: $1-2\text{ hours}$
• Duration: $3-5\text{ hours}$
• Nursing Nursing Rule: Must be administered within 15 minutes of mealtime or while the patient is actively eating to prevent severe hypoglycemia.

• Onset: $30-60\text{ minutes}$
• Peak: $2-4\text{ hours}$
• Duration: $5-8\text{ hours}$
• Key Feature: Regular Insulin is the ONLY insulin type given via IV route (e.g., IV push or continuous infusion for Diabetic Ketoacidosis).

• Onset: $1-2\text{ hours}$
• Peak: $4-12\text{ hours}$ (High risk for hypoglycemia in late afternoon/night)
• Duration: $14-24\text{ hours}$
• Appearance: Suspension is naturally cloudy.
• Mixing Technique: Draw Clear before Cloudy (Regular first, then NPH) to prevent contaminating short-acting insulin with NPH.