Metoprolol is a cardioselective β1-adrenergic blocking agent used for acute myocardial infarction (MI), heart failure, angina pectoris and mild to moderate hypertension. It may also be used for supraventricular and tachyarrhythmias and prophylaxis for migraine headaches. Metoprolol is structurally similar to bisoprolol, acebutolol and atenolol in that it has two substituents in the para position of the benzene ring. The β1-selectivity of these agents is thought to be due in part to the large substituents in the para position. At low doses, metoprolol selectively blocks cardiac β1-adrenergic receptors with little activity against β2-adrenergic receptors of the lungs and vascular smooth muscle. Unlike propranolol and pindolol, metoprolol does not exhibit membrane-stabilizing or intrinsic sympathomimetic activity. Membrane-stabilizing effects are only observed at doses much higher than those needed for β-adrenergic blocking activity. Metoprolol possesses a single chiral centre and is administered as a racemic mixture. Absorption: Well absorbed after oral administration. Distribution: Crosses the blood-brain barrier, crosses the placenta; small amounts enter breast milk. Metabolism and Excretion: Mostly metabolized by the liver (primarily by CYP2D6; the CYP2D6 enzyme system exhibits genetic polymorphism); ~7% of population may be poor metabolizers and may have significantly ↑ metoprolol concentrations and an ↑ risk of adverse effects. TIME/ACTION PROFILE (cardiovascular effects)When switching from immediate-release to extended-release product, the same total daily dose can be used PO: (Adults) Antihypertensive/antianginal– 25–100 mg/day as a single dose initially or 2 divided doses; may be ↑ q 7 days as needed up to 450 mg/day (immediate-release) or 400 mg/day (extended-release) (for angina, give in divided doses). MI– 25–50 mg (starting 15 min after last IV dose) q 6 hr for 48 hr, then 100 mg twice daily. Heart failure– 12.5–25 mg once daily (of extended-release), can be doubled every 2 wk up to 200 mg/day. Migraine prevention– 50–100 mg 2–4 times daily (unlabeled). IV: (Adults) MI– 5 mg q 2 min for 3 doses, followed by oral dosing. Tablets (tartrate): 25 mg, 50 mg, 100 mg Cost: Generic: All strengths $7.18/100Extended-release tablets (succinate; Toprol XL): 25 mg, 50 mg, 100 mg, 200 mg Cost: Generic: 25 mg $35.68/100, 50 mg $41.93/100, 100 mg $53.95/100, 200 mg $84.54/100Solution for injection: 1 mg/m LIn Combination with:hydrochlorothiazide (Dutoprol, Lopressor HCT). See combination drugs.metoprolol is a sample topic from the Davis's Drug Guide.
Metoprolol is a beta-blocker that affects the heart and circulation blood flow through arteries and veins. Metoprolol is used to treat angina chest pain and. Jul 23, 2014. Metoprolol is the generic form of the brand-name drug Lopressor, prescribed to treat high blood pressure and prevent angina chest pain.