Metoprolol: A Beta Blocker

The beta-blocker metoprolol is used to treat high blood pressure, certain cardiac arrhythmias, coronary artery disease, and acute and long-term treatment of a heart attack. In addition, the active ingredient can also be used to prevent migraine attacks. While taking metoprolol, side effects such as fatigue, dizziness, and headache may occur. In rare cases, a sharp drop in blood pressure or a significant decrease in heart rate may also occur. Learn more about the effects, side effects, and dosage of metoprolol here.

The active ingredient metoprolol

Metoprolol belongs to the group of beta-blockers. The active substance blocks the so-called beta-1 receptors in the body, to which messenger substances such as adrenaline and noradrenaline normally bind. Metoprolol weakens their effect and thus ensures a reduction in blood pressure, heart beat rate, heart beat volume and excitation conduction velocity.

What does metoprolol work against?

Metoprolol is prescribed similarly to ramipril or amlodipine to treat high blood pressure. Due to the fact that the active ingredient also leads to a sparing of the heart, it is also used to relieve the heart after a heart attack and to prevent heart attacks. It is also suitable for the treatment of tachycardic arrhythmias (palpitations), weak heart failure or coronary heart disease. In addition, metoprolol is also used to prevent migraine attacks. According to current findings, during a migraine attack the blood vessels in the meninges are severely dilated. By taking metoprolol, there is a constriction of the vessels and thus an associated relief of the symptoms.

Side effects of metoprolol

Taking metoprolol may be associated with a variety of side effects. Initially, central nervous disturbances may occur, such as:

  • Fatigue
  • Dizziness
  • Headache
  • Confusion
  • Sweating
  • Sleep disturbances
  • Depressive moods
  • Hallucinations

Occasionally may cause gastrointestinal side effects such as diarrhea and constipation, nausea and vomiting. Also occasionally, skin rashes, redness and itching have also been observed. In addition, side effects such as muscle weakness and muscle cramps, as well as limb insensitivity, may occur.

Metoprolol: Rare Side Effects

In rare cases, more severe side effects may also occur as a result of taking metoprolol. These include:

  • A severe drop in blood pressure
  • A sharp drop in heart rate
  • Palpitations
  • An increase in the weakness of the heart muscle
  • Disturbances in the conduction of excitation
  • Shortness of breath under stress

For a detailed overview of all side effects, please take a look at the package insert of your medication or ask your doctor or pharmacist for advice.

Dosage of metoprolol

How exactly to dose metoprolol always depends on the underlying condition. Therefore, please talk to your doctor about the exact dosage and consider the following information as general guidelines only.

  • High blood pressure and coronary artery disease: take either 50 milligrams once or twice daily or 100 milligrams of metoprolol once daily. The dose may be increased up to 100 milligrams twice daily.
  • Cardiac arrhythmias: Take 100 milligrams of metoprolol once or twice daily.
  • Heart attack (acute and long-term treatment): how to take metoprolol during acute treatment of a heart attack, please consult with your attending physician. Following acute therapy, take 100 milligrams twice daily.
  • Migraine prophylaxis: take 100 milligrams of metoprolol once or twice daily.

What to do in case of metoprolol overdose.

If you have taken too high a dose, you should immediately notify a doctor or emergency physician. This is because, depending on the dose, you may experience a severe drop in blood pressure as well as a low heart rate or even cardiac arrest. In addition, breathing difficulties, impaired consciousness, vomiting and spasms of the bronchial muscles may occur.

Discontinuing metoprolol

In general, the dosage of metoprolol should be changed only after consultation with the treating physician.After a prolonged treatment, the active substance should never be suddenly discontinued, as otherwise dangerous side effects may occur: For example, there may be a rapid rise in blood pressure again or reduced blood flow to the heart muscle. This can worsen existing angina pectoris or lead to a heart attack. Therefore, the dose should be slowly reduced step by step before the drug is finally discontinued altogether.

Metoprolol: Contraindications

Metoprolol must not be used if there is hypersensitivity to the active substance. In addition, the active ingredient must not be taken for certain heart problems, including.

  • Severe heart muscle weakness that has not been adequately treated.
  • A cardiogenic shock
  • A slowed heartbeat (bradycardia)
  • Excitation conduction disorders

In addition, metoprolol should not be taken for a number of other conditions. These include:

Only after a careful risk-benefit analysis by the treating physician should metoprolol be used in diabetics with fluctuating blood glucose levels, patients with hyperthyroidism, impaired renal function, bronchial muscle spasms, or psoriasis. The same applies to patients being treated with inhalational anesthetics or currently undergoing desensitization.

Danger in diabetes and impaired liver and kidney function.

In diabetics, blood glucose levels should be checked regularly while taking the drug. This is because the use of metoprolol may increase the risk of hypoglycemia. This is due to the fact that the effect of insulin or other antidiabetic drugs may be prolonged or increased. In addition, warning signs of hypoglycemia such as muscle tremors or palpitations may be masked. Caution should also be exercised in patients with hepatic or renal impairment: In patients with liver dysfunction, the dosage may need to be lowered because the drug is more poorly metabolized. In the case of reduced kidney function, regular monitoring of the kidneys is recommended. Possibly, the use of the beta-blocker may namely worsen the kidney function.

Drug interactions with metoprolol

To avoid interactions, no other beta blockers should be administered while taking metoprolol. It is also preferable to avoid administration of other antiarrhythmic agents-especially calcium antagonists (both of the verapamil, diltiazem, and nifedipine types). Problems may also occur with concomitant use of:

  • Tricyclic antidepressants
  • Neuroleptics
  • Antihistamines
  • ACE inhibitors (for example, ramipril)
  • Narcotics
  • Diuretics
  • Vasodilators
  • Phenothiazines
  • Barbiturates

Also, the active ingredients floctafenine, sultopride and nitroglycerin should not be taken together with metoprolol. Otherwise, depending on the drug, a sharp drop in blood pressure, a reduction in heart rate or cardiac arrhythmia may occur. Interactions may also occur with cardiac glycosides and the active ingredients reserpine, guanfacine, guanethidine, alpha-methyldopa and clonidine. Interactions may also include a decrease in heart rate and problems with conduction. Simultaneous use of MAO inhibitors, epinephrine, or norepinephrine may cause a sharp increase in blood pressure. Cimetidine, on the other hand, may potentiate the effects of metoprolol.

Metoprolol in pregnancy

Whether there are risks to the unborn child from taking metoprolol during pregnancy has not yet been sufficiently researched. Therefore, you should refrain from taking the drug during pregnancy or at least take it only after a careful risk-benefit analysis by your treating physician. Under certain circumstances, metoprolol can reduce blood flow to the placenta and thus cause growth disorders in the unborn child.If the active substance has to be taken during pregnancy, it should in any case be discontinued two to three days before the expected date of birth in order to avoid severe side effects for the infant. If this is not possible, the child must be closely monitored for two to three days after birth.

Metoprolol during breastfeeding

Metoprolol should also be avoided during breastfeeding, if possible, because the active ingredient passes into breast milk. If it is absolutely necessary to take it, breastfeeding should be discontinued or the child should not be breastfed until three to four hours after taking it. By then, the concentration of the active ingredient has already dropped significantly. In such a case, the infant should be checked regularly by a physician with regard to a blockade of the beta receptors.