Known brand names include Lopressor, Toprol, and Kapspargo.
A beta blocker that slows the heart and lowers blood pressure. It treats high blood pressure and angina, is used after a heart attack, and the extended-release form treats heart failure.
First-line. Metoprolol succinate is one of the evidence-based beta blockers for heart failure with reduced ejection fraction.
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Labeled use. Tartrate, alone or after IV metoprolol, in hemodynamically stable patients.
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Labeled use. Long-term treatment to reduce attacks and improve exercise tolerance.
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Choose metoprolol succinate for heart failure with reduced ejection fraction, where it lowers mortality. Metoprolol fits well after MI and for rate control or angina. It is not usually a first choice for uncomplicated hypertension. Being beta-1 selective, it is preferred over nonselective beta blockers in COPD or asthma, at the lowest dose.
Blocks beta-1 receptors in the heart, which slows the sinus rate and AV node conduction and reduces cardiac output. Selectivity is relative: at higher levels it also blocks beta-2 receptors in the airways and blood vessels. It has no intrinsic sympathomimetic activity.
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The label does not describe a narrow therapeutic index or direct dosing by measured blood levels of the drug.
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Doses come from the FDA label. Study tool, not for clinical decisions.
None. Bioavailability and half-life are not meaningfully changed in renal failure.
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Start below the usual dose and increase gradually. Metoprolol is cleared by the liver, so levels may rise substantially when hepatic function is poor.
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None on the current Lopressor or Toprol-XL labels. Abrupt cessation is a labeled warning instead.
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No single antidote. Treat bradycardia with atropine, adrenergic drugs, or pacing; hypotension with vasopressors such as norepinephrine; heart failure or shock with fluids, glucagon, and dobutamine; and bronchospasm with bronchodilators. Hemodialysis does not help.
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Observational studies have not linked metoprolol to adverse developmental outcomes. Untreated hypertension or MI in pregnancy carries its own risks.
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Present in breast milk at about 0.5% to 2% of the mother's weight-adjusted dose. No infant adverse reactions have been identified.
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Lopressor (tartrate) is not established in children. Toprol-XL (succinate) for hypertension from age 6: start 1 mg/kg once daily, at most 50 mg; doses above 2 mg/kg or 200 mg are unstudied.
No age-related differences in safety or effectiveness were found in trials. Start low and titrate cautiously given more liver, kidney, and heart disease in older adults.
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