METOPROLOL (LOPRESSOR): What is used for?

What is Metoprolol?

Metoprolol is a drug used for the treatment of arrhythmias, angina pectoris, high blood pressure, cardiac arrhythmias, preventive treatment of myocardial infarction, migraine prophylaxis and hyperthyroidism.
The products ingredients are: Metoprolol fumarate, Metoprolol succinate, Metoprolol tartrate.

The brand names in the United States are: Lopressor, Toprol-XL, Metoprolol Tartrate, Metoprolol Succinate ER.

Mechanism of Action (MOA)

Cardioselective that acts on ß1 receptors of the heart. No membrane stabilizing effect, no intrinsic sympathomimetic activity.

Therapeutic indications, uses and benefits

Oral: High blood pressure; angina pectoris, cardiac arrhythmias (supraventricular tachycardia), maintenance treatment after myocardial infarction, migraine prophylaxis.

Delayed form: functional cardiac disorders with palpitations.

Non-retardant form: hyperthyroidism.

Intravenous (IV): arrhythmias (supraventricular tachycardia), confirmed or suspected myocardial infarction.

Metoprolol Dosage 

– Arrhythmias (supraventricular tachycardia: initial: 5 mg at 1-2 mg/min rate. Repeat if necessary up to 10-15 mg/5 min. Max. 20 mg/day.

– Confirmed or suspected myocardial infarction: 12 h after infarction 3 boluses of 5 mg/2 min. At 15 min 50 mg oral/6 h (2 days).

– High blood pressure (HBP): 50-100 mg/12 h or 100-200 mg/day; delay: 47.5-95 mg metoprolol succinate (50-100 mg metoprolol tartrate) once a day. If necessary, metoprolol succinate (200 mg metoprolol tartrate) can be increased by 190 mg once a day and/or other antihypertensive agents can be added.

– Angina pectoris: 50-100 mg/12 h; delay: 95-190 mg metoprolol succinate (100-200 mg metoprolol tartrate)/day in a single dose.

– Cardiac arrhythmias: 50-100 mg/12 h; delay: 95-190 mg metoprolol succinate (100-200 mg metoprolol tartrate)/day in a single dose.

– Preventive treatment of sequelae of myocardial infarction: maintenance: 100 mg/12 h.; delay: maintenance: 190 mg of metoprolol succinate (200 mg of metoprolol tartrate)/day in one dose.

– Migraine prophylaxis: 50-100 mg/12 h; delay: 95-190 mg metoprolol succinate (100-200 mg metoprolol tartrate)/day, in a single dose.

– Functional heart disorders with palpitations: delay: 95 mg metoprolol succinate (100 mg metoprolol tartrate)/day, in a single dose. If necessary, metoprolol succinate (200 mg metoprolol tartrate) can be increased to 190 mg.

– Hyperthyroidism: 150-200 mg/day (3-4 intakes).

Method of administration

Oral use

– Tablets: administer on an empty stomach. The dose must be adjusted individually to each patient.

– Prolonged-release tablets: administer a single daily dose, can be taken with or without food, be ingested with the aid of liquids. The tablets or their halves should not be chewed or crushed.


  • Hypersensitivity to this active ingredient, other beta-blockers.
  • Second and third degree atrioventricular block.
  • Decompensated cardiac insufficiency (pulmonary edema, hypoperfusion or hypotension).
  • With continuous or intermittent inotropic treatment that acts by antagonism with ß receptors.
  • Sinus bradycardia.
  • Sick sinus syndrome (unless a permanent pacemaker is implanted), cardiogenic shock, severe peripheral arterial circulatory disorder.
  • Myocardial infarction with heart rate < 45 ppm, an interval P-Q > 0.24 sec or systolic pressure < 100 mm Hg.

Warnings and precautions of Metoprolol

  • Severe liver failure.
  • Asthma (dose adjustment).
  • Heart failure.
  • Pheochromocytoma (given with an alpha blocker).
  • Surgical intervention (inform the anaesthetist who is being treated).
  • May aggravate symptoms of peripheral arterial circulatory disorders and rarely aggravate pre-existing atrioventricular conduction disorders of moderate degree.
  • If bradycardia worsens, give lower doses or discontinue treatment gradually.
  • Risk of coronary events during ß-blocker removal.
  • Cardiac monitoring.

Liver failure

Severe impairment of liver function (hepatic anastomosis) should be considered dose reduction.


  • In association with clonidine if it is necessary to discontinue treatment, first discontinue the ß-blocker several days before.
  • Negative inotropic and negative dromootropic potency of: quinidine and amiodarone.
  • Increased cardiopressive effect with: inhaled anesthetics.
  • Plasma concentration decreased by: rifampicin.
  • Plasma concentration increased by: cimetidine.
  • Reduced effect of: indomethacin.
  • Modifies glucose concentration in diabetics treated with: hypoglycemic.
  • Increases toxicity of: lidocaine.
  • Calcium antagonists of the verapamil type should not be administered by IV with beta-blockers.


May cause side effects in the fetus.
If necessary, it can be used.


It should not be used during lactation unless its use is considered essential.
ß-blockers may cause side effects such as bradycardia in the infant. However, the amount ingested through breast milk is negligible in relation to a possible ß-blocking effect on the child, if the mother is treated with at usual therapeutic doses.

Effects on driving ability

Patients should test their reaction before driving vehicles or using machines due to possible onset of dizziness or tiredness.

Adverse reactions and side effects of Metoprolol

Bradycardia, postural hypotension, cold hands and feet, palpitations. Tiredness, headaches; nausea, abdominal pain, diarrhea, constipation; effort dyspnea.


Source: The content of this active ingredient has been written taking into account the clinical and molecular information of all medicines authorised and marketed in the United States under the Unique Ingredient Identifier (UNII) by the Substance Registration System (SRS) of the Food and Drug Administration (FDA) and the United States Pharmacopeia (USP).

In order to know in detail the information authorized by the FDA for each drug, you should consult the corresponding medication guide authorized by the FDA.


PubChem CID: 4171
NCI Thesaurus: C61845


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