Why are the uses for metoprolol (Lopressor, Toprol XL)?

What are the side effects of metoprolol (Lopressor, Toprol XL)?

Metoprolol is generally well tolerated. Side effects include

Possible serious adverse effects include

Metoprolol can aggravate breathing difficulties in patients with asthma, chronic bronchitis, or emphysema.


  • In patients with existing slow heart rates (bradycardias) and heart blocks (defects in the electrical conduction of the heart), metoprolol can cause dangerously slow heart rates, and even shock. Metoprolol reduces the force of heart muscle contraction and can aggravate symptoms of heart failure. In patients with coronary artery disease, abruptly stopping metoprolol can suddenly worsen angina, and occasionally precipitate heart attacks. If it is necessary to discontinue metoprolol, its dosage should be reduced gradually over several weeks.
  • Initiation of high-dose extended release metoprolol in patients undergoing non-cardiac surgery is associated with bradycardia (slow heart rate), hypotension, stroke, and death. However, long-term therapy with metoprolol should not be routinely withdrawn prior to major surgery. Impaired ability of the heart to respond to reflex adrenergic stimuli may increase the risks of general anesthesia and surgery.


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What is the dosage for metoprolol (Lopressor, Toprol XL)?

  • Metoprolol should be taken before meals or at bedtime.
  • The dose for treating hypertension is 100-450 mg daily in single or divided doses.
  • Angina is treated with 100-400 mg daily in two divided doses.
  • Heart attack (acute myocardial infarction) is treated with three 5 mg injections administered 2 minutes apart followed by treatment with 50 mg oral metoprolol every 6 hours for 48 hours. After 48 hours, patients should receive 100 mg orally twice daily for at least 3 months.
  • The dose for congestive heart failure is 25 mg/daily initially. Then the dose is increased every 2 weeks to reach a target dose of 200 mg/daily orally.
  • Hyperthyroidism is treated with 25 to 30 mg by mouth every 6 hours.

Which drugs or supplements interact with metoprolol (Lopressor, Toprol XL)?

Is metoprolol (Lopressor, Toprol XL) safe to use during pregnancy or while breastfeeding?

  • Safe use of metoprolol during pregnancy has not been established.
  • Small quantities of metoprolol are excreted in breast milk and may potentially cause adverse effects in the infant.

What else should I know about metoprolol (Lopressor, Toprol XL)?

  • Metoprolol (Lopressor, Toprol XL) is available as:
    • Tablets: 25, 50, and 100 mg.
    • Tablets (extended release): 25, 50, 100, and 200 mg.
    • Injection: 1 mg/ml
  • Metoprolol (Lopressor, Toprol XL) Tablets should be stored between 15 C and 30 C (59 F and 86 F). The tablets should be protected from moisture and dispensed in tight, light-resistant containers
  • Metropolol is available in the US under the brand names Lopressor and Toprol XL.
  • Metropolol is available in generic form.


Salt and sodium are the same. See Answer


Metoprolol (Lopressor, Toprol XL) is a beta-adrenergic blocking agent drug, which blocks the action of the sympathetic nervous system (a portion of the involuntary nervous system). Metoprolol is prescribed to treat high blood pressure (hypertension), heart pain (angina), heart rhythm disorders, and some neurological conditions. Side effects include fever, impotence, sore throat, nausea, depression, insomnia, constipation, memory loss, and high blood pressure.

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See more info: metoprolol on RxList
Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine


FDA Prescribing Information