Norepinephrine is an artificial analogue of the hormone that is produced in the human adrenal glands. When it is released into the bloodstream, a narrowing of blood vessels occurs, the heart rate becomes more frequent, and blood pressure rises. The reaction occurs almost instantly, so the synthetic drug is used in emergency situations, for example, when cardiac arrest or collapse.

What is Noradrenaline, a description in your own words

Norepinephrine is synthesized from dopamine, is a precursor to adrenaline. These chemical compounds make the body awake, increase blood pressure in arteries and veins, and stimulate myocardial contraction. The physiological release of hormones from the adrenal glands into the bloodstream occurs with a change in body position, fear, severe pain. This allows for some time to not pay attention to pain, as well as maintain the desired level of blood pressure. The action is instantaneous, however, has a short-term effect.

The differences between norepinephrine and adrenaline are to varying degrees, the effect on organs and systems.

When using the first:

  • stronger vasoconstrictor effect;
  • weaker effect on myocardial contraction;
  • virtually no effect on smooth muscles, which is mainly in the bronchi and gastrointestinal tract;
  • imperceptible changes in the metabolism;
  • less need of cells of various tissues for additional oxygen.

With the intravenous administration of norepinephrine, it is possible to observe its effect on the body practically from the first second - the pulse quickens and pressure rises.But the effect lasts only a few minutes, so in medical practice synthetic hormone is used as a stimulant. This allows you to gain time to eliminate the cause of the collapse.

Why is the drug prescribed?

Synthetic norepinephrine is used to quickly correct blood pressure in the event of a sharp drop.

This can happen for the following reasons:

  • severe injury, pain shock;
  • poisoning, leading to inhibition of vasomotor centers;
  • complications during surgery;
  • critical pressure reduction for no apparent reason;
  • postoperative period after removal of pheochromocytoma.

Norepinephrine and adrenaline are interchangeable drugs, however, due to differences in the strength of influence on individual organs, in some situations it is better to choose one of them.

For example, adrenaline is better for cardiac arrest, since it actively stimulates myocardial contractions, and in case of collapse, norepinephrine with its sharp vasoconstrictor effect.

Instructions for use of Norepinephrine

Norepinephrine can be administered only intravenously, since if it enters the muscles or subcutaneous tissue, the drug causes necrotization of the surrounding tissues. And also you can not inject the medicine in its pure form, immediately before injection it must be diluted with isotonic NaCL solution or 5% glucose.

Hormone dilution is different and depends on the route of administration:

  • ordinary dropper - from a bottle containing 500 ml of a solution, draw 40 ml of liquid and replace it with 40 ml of 1% norepinephrine;
  • infusion pump — 46 ml of the solution is added to a 50 ml syringe, and then 4 ml of 1% norepinephrine are added;
  • with a single injection to raise blood pressure, 1 ml of the drug is diluted with 9 ml of solution.

It is strictly forbidden to mix synthetic hormone with any other medicines in the same syringe.

It is even recommended to use a separate catheter for the administration of norepinephrine.

At the beginning of therapy, the drug is administered very slowly, observing the reaction of the body. If no side effects occur, the speed can be gradually increased. Treatment lasts from several hours to a week, an indication to stop the infusion is the patient’s ability to keep a normal level of blood pressure.

The tool is also canceled gradually, since a sharp cessation of administration leads to a collapse.

Drug interaction

Artificial norepinephrine can interact with other drugs, which is important to consider when combining therapy.

With simultaneous use, the following reactions are possible:

  • antidepressants - a significant increase in the risk of failures in the innervation of the heart, arrhythmias;
  • alpha-adrenergic blockers - level the vasoconstrictive effect of the hormone;
  • nitrates - an increase in the oxygen demand of the heart muscle;
  • diuretics (diuretics) and drugs that reduce blood pressure - a decrease in the therapeutic effect of drugs;
  • agents containing thyroid hormones (thyroxine, triiodothyronine) - the development of angina pectoris and coronary insufficiency;
  • inhalation anesthesia - the appearance of ventricular arrhythmias.

In order to avoid unforeseen situations, the intake of other medicines should be discontinued during treatment with norepinephrine. If this is not possible, you need to carefully study the possible types of interaction.

Contraindications, side effects and overdose

Norepinephrine is a medication that has a strong effect on the vital organs of a person. Therefore, the dosage should be very accurate, and the frequency of administration should correspond to the treatment regimen.

And also the drug has contraindications, in the presence of which it is forbidden to use it:

  • hypovolemia (reduced blood volume in the body) - develops with bleeding, severe dehydration. The hormone can only be started at the same time as the means for correcting BCC (the volume of blood that circulates);
  • high concentration of carbon dioxide in the body, prolonged oxygen starvation;
  • during anesthesia, which is carried out using halotane or cyclopropane;
  • individual sensitivity to the components of the drug.

With extreme caution and under the careful supervision of a specialist, norepinephrine should be administered with such problems:

  • acute heart failure;
  • a recent history of myocardial infarction;
  • tendency to thrombosis, thrombosis of important vessels in the past;
  • pregnant women - only in critical situations when the life of the mother and fetus is in danger.

A single administration of the drug does not affect breastfeeding, however, with prolonged therapy, the baby should be temporarily transferred to artificial food.

Too rapid intravenous administration of norepinephrine leads to unpleasant sensations in the patient - headache, cold in the arms and legs, increased heart rate. After slowing down the infusion, the symptoms disappear.

Hypersensitive people may develop adverse reactions to synthetic hormone:

  • CNS - sleep problems, anxiety, anorexia, disorientation in space, cephalgia, vomiting, which does not bring relief;
  • acute angle-closure glaucoma;
  • anuria - urinary retention;
  • respiratory organs - pain in the mediastinum (chest area), the appearance of shortness of breath, the development of acute respiratory failure;
  • heart and blood vessels - hypertensive crisis, heart failure, ischemia.

In case of an overdose of norepinephrine, an aggravation of adverse reactions is observed - acute anuria, high blood pressure, lack of air, vasospasm. Help is to immediately stop the infusion and conduct symptomatic therapy.

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