A patient with hypertension and angina is prescribed metoprolol. What is the primary mechanism of action of this drug?

The correct answer to the question "A patient with hypertension and angina is prescribed metoprolol. What is the primary mechanism of action of this drug?" is Option C: Selective antagonism of beta-1 adrenergic receptors.

The other options — A) Direct arterial vasodilation, B) Inhibition of angiotensin-converting enzyme, D) Blockade of calcium channels in cardiac muscle — are incorrect for this USMLE Exam Prep question. As explained above: Metoprolol is a selective beta-1 adrenergic receptor antagonist (beta-blocker). It primarily blocks beta-1 receptors in the heart, decreasing heart rate, contractility, and blood pressure, which is b…