CPEN Pharmacology Practice Questions (80 Flashcards)

Ipratropium bromide is a muscarinic antagonist that provides synergistic bronchodilation with SABAs. Guidelines (GINA/EPR-4) recommend 3 doses (or 1 continuous) in the first hour for severe exacerbations. Beyond the initial phase, additional doses do not show significant clinical benefit or further reduction in hospitalization rates. Exam Tip: BCEN often tests the 3-dose limit for ipratropium in the ED setting. Rationale: Maximizing receptor blockade early yields the best outcomes; continued use increases side effects (dry mouth, tachycardia) without therapeutic gain.

Alpha-1: Vasoconstriction (increases SVR, decreases mucosal edema/upper airway swelling). Beta-1: Increased heart rate and contractility (increases CO). Beta-2: Bronchodilation and stabilization of mast cells/basophils (stops further mediator release). Exam Tip: Understand that Alpha-1 effects are crucial for treating the distributive shock component, while Beta-2 stabilizes the cells to stop the reaction at the source. This triple-action makes it the only first-line treatment.

Calculation: Units = Weight (kg) x Desired % Increase x 1.0. For this patient: 30 kg x 100% x 1.0 = 3,000 units. Clinical Pearl: Unlike Factor VIII, 1 unit/kg of Factor IX raises the plasma level by only 1%. Factor IX has a longer half-life (approx. 18–24 hours) than Factor VIII, typically requiring dosing every 24 hours. Major bleeds (iliopsoas, intracranial, neck) always require 80–100% target levels.

Recheck glucose within 15-30 minutes after the bolus. Target range is typically >70 mg/dL (or >45-50 mg/dL in neonates, though 70+ is safer). Clinical Pearl: Dextrose boluses have a short duration of action (approx. 20-30 mins). Continuous monitoring is essential to detect rebound effects, especially in cases of insulin or oral hypoglycemic ingestion.

The antidote is Deferoxamine, administered via continuous IV infusion (preferred over IM). It chelates iron to form ferrioxamine, which is excreted by the kidneys. A classic sign of chelation is Vin Rose urine (a reddish-orange color). CPEN Strategy: BCEN may ask about the Vin Rose urine, but remember it is not present in all cases and its absence does not mean the antidote is failing. A major complication of rapid Deferoxamine infusion is hypotension, which requires slowing the rate and providing fluid boluses.