Description of the medicine: Norepinephrine hydrotartrate (Noradrenalini hydrotartras)
NORADRENALINE HYDROTARTRATE (Noradrenalini hydrotartras). l-1- (3,4-dioxiphenyl) -2-aminoethanol hydrotartrate.
Synonyms: Arterenol, Noradrenalinum hydrotartaricum, Levarterenol, Levarterenoli bitartras, Levarterenol bitartrate, Levophed, Norartrinal, Norepinephrine, Norexadrine, etc.
Flavourless white or almost white crystalline powder. Easily soluble in water, little in alcohol. Easily changes under the influence of light and oxygen. Aqueous solutions (pH 3, 0 - 4, 5) are sterilized at +100 ° C for 15 minutes.
The chemical structure of norepinephrine differs from adrenaline in the absence of a methyl group at the nitrogen atom, an amino group of the side chain.
The action of norepinephrine is associated with a predominant effect on a -adrenoreceptors (namely, on a 1 -adrenoreceptors). It differs from adrenaline by a stronger vasoconstrictor and pressor effect, a less stimulating effect on heart contractions, a weak bronchodilator effect, a weak effect on metabolism (the absence of a pronounced hyperglycemic effect).
The cardiotropic effect of norepinephrine is associated with a stimulating effect on the b-adrenergic receptors of the heart, but the b-adrenergic stimulating effect is masked by reflex bradycardia and an increase in vagus nerve tone caused by increased blood pressure.
The introduction of norepinephrine causes an increase in cardiac output, due to an increase in blood pressure, perfusion pressure in the coronary arteries increases. However, peripheral vascular resistance and central venous pressure increase significantly.
It is used to increase blood pressure during acute decrease due to surgical interventions, injuries, poisoning, accompanied by inhibition of vasomotor centers, etc., as well as to stabilize blood pressure during surgical interventions on the sympathetic nervous system after removal of pheochromocytoma, etc.
Norepinephrine is a very effective way to increase blood pressure and strengthen heart contractions. However, an increase in blood pressure is mainly associated with an increase in peripheral vascular resistance and heart rate. Under the influence of norepinephrine, blood flow in the renal and mesenteric vessels also decreases. The occurrence of ventricular arrhythmias is possible. Therefore, with cardiogenic shock, especially in severe cases, the use of norepinephrine is considered inappropriate (E.I. Chazov). Typically, severe cases of cardiogenic (and hemorrhagic) shock are accompanied by a vasoconstrictor reaction of peripheral vessels. The introduction of norepinephrine and other substances that increase the resistance of peripheral vessels in these cases can have a negative effect. It should also be borne in mind that under the influence of norepinephrine (and other sympathomimetic amines), the need for myocardium in oxygen increases.
If there are indications, norepinephrine is administered intravenously (drip).