A 68-year-old man with NYHA class III heart failure and reduced ejection fraction is started on carvedilol. Which pharmacological property of carvedilol contributes to afterload reduction and distinguishes it from pure beta-blockers like metoprolol?
- A Beta-1 partial agonism
- B Muscarinic receptor agonism
- C Alpha-1 receptor blockade ✓
- D Potassium channel opening
Correct answer: C. Alpha-1 receptor blockade
Explanation
Carvedilol is a non-selective beta-blocker with additional alpha-1 blocking activity. Alpha-1 blockade causes arteriolar vasodilation, reducing afterload. This dual action differentiates carvedilol from cardio-selective beta-blockers like metoprolol and contributes to its mortality benefit in heart failure by reducing cardiac workload.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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