How does Metoprolol primarily exert its antihypertensive effect?

Metoprolol primarily exerts its antihypertensive effect by blocking β-adrenergic receptors, specifically the β1 subtype. This action reduces the heart's workload and decreases cardiac output. By blocking these receptors in the heart, Metoprolol decreases heart rate and contractility, leading to lower blood pressure.

Additionally, blocking β-adrenergic receptors reduces the secretion of renin from the kidneys, which is another pathway for lowering blood pressure, but the cornerstone of Metoprolol’s effect in the context of hypertension is its direct action on the heart rather than renal mechanisms.

In contrast to increasing heart rate or acting as a vasodilator, Metoprolol actually does the opposite: it slows the heart rate and does not cause vasodilation directly. Therefore, the main mechanism through which Metoprolol facilitates blood pressure reduction is through β-adrenergic blockade.