A cardioselective competitive beta-1 adrenergic receptor antagonist with antihypertensive properties and devoid of intrinsic sympathomimetic activity. Metoprolol antagonizes beta 1-adrenergic receptors in the myocardium, thereby reducing the rate and force of myocardial contraction leading to a reduction in cardiac output. This agent may also reduce the secretion of renin with subsequent reduction in levels of angiotensin II thereby preventing vasoconstriction and aldosterone secretion.