Pharmacology · single question
A 56-year-old female with hypertension takes Metoprolol (Lopressor). What is the mechanism of action controlling her hypertension?
Show answer and explanation
Correct answer: A. Competitively inhibits β2 adrenergic receptors
- A. Correct. Metoprolol is a cardioselective β1-blocker. It competitively inhibits β1 receptors in the heart, reducing heart rate and cardiac output, thereby lowering blood pressure.
- B. Incorrect. Nitric oxide release is the MOA of nitrates (nitroglycerin).
- C. Incorrect. Calcium channel blockade is the MOA of amlodipine, verapamil, diltiazem.
- D. Incorrect. Metoprolol is selective for β1. Non-selective blockers (propranolol) also block β2.