This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug, changing your diet or commencing any course of treatment. When food is taken with this beta-blocker medicine, the amount of medicine in your bloodstream may be higher than if it is taken on an empty stomach. It may be due to an increase in the amount of medicine you absorb into your bloodstream or a decrease in the speed at which your body processes (metabolizes) it. Always take this medicine with meals or always take it on an empty stomach (one hour before or two hours after food). This will help you to avoid unwanted changes in the level of this medicine in your blood. Contact your healthcare professional (e.g., doctor or pharmacist) for more information. Your healthcare professionals may be aware of this interaction and may be monitoring you for it. Three extended release formulations of metoprolol (95 mg metoprolol succinate) with different in vitro release rates were administered to ten healthy males (20–29 years) as single oral doses. The bioavailability properties of the three formulations were evaluated in relation to an intravenous dose (10 mg metoprolol tartrate) and an oral solution (95 mg metoprolol succinate). Both the rate and extent of metoprolol absorption were related to the drug release rate as shown by the plasma concentration-time profiles and resultant pharmacokinetic variables. Individual absorption-time profiles reflected well the corresponding in vitro release curves, showing a good correlation over the entire time interval for all three formulations. For the slowest formulations, drug absorption continued at very delayed times (24–30 h) in most individuals, confirming the good distal gastrointestinal absorption of metoprolol. A reduced bioavailability was seen with all extended release formulations compared with the solution and was probably caused by increased hepatic first-pass metabolism. Incomplete absorption may also contribute to the more markedly reduced bioavailability of the slowest formulation.
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 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.
Metoprolol is absorbed fully after oral administration. Within the therapeutic dosage range, the plasma concentrations increase in a linear manner in relation to. The absorption of metoprolol was unaffected by food intake, with 80-90% of the. 5 The in vivo release and absorption of drug from the Oros system, and its.