The nurse manager is conducting an educational session for the nurses on non-selective beta-adrenergic blockers ( $\beta$ blockers). How should the nurse manager accurately describe the mechanism of action of these medications? List the options in order from first to last.
Correct Answer: C
Rationale: Non-selective beta-adrenergic blockers (e.g., propranolol) inhibit the sympathetic nervous system's effects on betaâ‚ (heart) and betaâ‚‚ (lungs, vessels) receptors. The mechanism sequence is: (1) Betaâ‚ and betaâ‚‚ receptor sites are blocked (C), (2) Epinephrine and norepinephrine actions are blocked (B), (3) Heart rate and blood pressure are decreased (A), (4) Cardiac workload and oxygen demand decreases (D). Blocking beta receptors (C) is the initial step, preventing catecholamines (B) from binding, which reduces heart rate and vasoconstriction (A), ultimately lowering myocardial oxygen demand (D). Incorrect sequencing, like starting with heart rate reduction, skips the pharmacological basis. The CSV requires one answer, so C is chosen as the foundational step. Rationale: Beta blockade directly inhibits receptor activation, a primary action taught in pharmacology education, leading to downstream effects critical for conditions like hypertension or angina, ensuring nurses understand the drug's systemic impact.