Metoprolol is best described as which type of receptor blocker?

Metoprolol is best described as which type of receptor blocker?

• A. Alpha-1 blocker
• B. Alpha-2 blocker
• C. Beta-1 selective blocker
• D. Beta-2 blocker

Answer: (C)

Metoprolol is best described as a beta-1 selective blocker. It mainly binds to beta-1 adrenergic receptors in the heart, so it reduces heart rate, slows conduction through the AV node, and lowers myocardial contractility and oxygen demand. This cardioselectivity means it has less effect on beta-2 receptors in the lungs and vasculature at typical doses, which lowers the risk of bronchospasm compared with nonselective beta blockers. At higher doses, the selectivity can lessen, potentially affecting beta-2 receptors as well. It is not an alpha blocker, and it is not a beta-2 blocker.

Metoprolol is best described as a beta-1 selective blocker. It mainly binds to beta-1 adrenergic receptors in the heart, so it reduces heart rate, slows conduction through the AV node, and lowers myocardial contractility and oxygen demand. This cardioselectivity means it has less effect on beta-2 receptors in the lungs and vasculature at typical doses, which lowers the risk of bronchospasm compared with nonselective beta blockers. At higher doses, the selectivity can lessen, potentially affecting beta-2 receptors as well. It is not an alpha blocker, and it is not a beta-2 blocker.