Cardiac Vascular Nursing Exam Pharmacology & Medications Flashcards

Which mechanism of action explains why beta-blockers reduce mortality in heart failure with reduced ejection fraction?

Answer: Blocking catecholamine overstimulation reduces cardiac remodeling, improves ejection fraction, and prevents arrhythmic death

Chronic sympathetic overstimulation in HFrEF causes maladaptive remodeling; beta-blockers block this, reversing remodeling, improving EF, and reducing sudden cardiac death.

A nurse is administering IV heparin for STEMI management. Which laboratory value must be monitored to guide dosing?

Answer: Activated partial thromboplastin time (aPTT)

Unfractionated heparin's anticoagulant effect is monitored with aPTT, targeting 60–100 seconds (1.5–2.5× control) to maintain therapeutic anticoagulation during ACS management.

Which class of medication is contraindicated in patients with bilateral renal artery stenosis and must be avoided when initiating heart failure treatment?

Answer: ACE inhibitors and ARBs

ACE inhibitors and ARBs block efferent arteriolar constriction that maintains GFR in renal artery stenosis; in bilateral disease this can precipitate acute kidney injury.

A patient on amiodarone for atrial fibrillation also takes warfarin. The nurse anticipates which drug interaction?

Answer: Amiodarone inhibits warfarin metabolism, increasing INR and bleeding risk

Amiodarone inhibits CYP2C9, the primary enzyme metabolizing warfarin's S-enantiomer, causing warfarin accumulation and significantly elevated INR requiring dose reduction.

Which pharmacological property of digoxin makes narrow therapeutic index monitoring essential?

Answer: Digoxin has a narrow margin between therapeutic and toxic plasma concentrations, with toxicity enhanced by hypokalemia

Therapeutic digoxin levels (0.5–2 ng/mL) are close to toxic levels, and hypokalemia sensitizes the Na/K-ATPase pump to digoxin, dramatically increasing toxicity risk.

Nitroglycerin relieves angina primarily through which mechanism?

Answer: Venous dilation reduces cardiac preload, decreasing myocardial oxygen demand

Nitroglycerin releases nitric oxide causing smooth muscle relaxation predominantly in venous capacitance vessels, reducing preload and ventricular filling pressure, lowering myocardial oxygen demand.