Cardiac glycosides in heart failure

Acute or chronic heart failure is caused by a number of pathological phenomena that disrupt the normal rhythm of the cardiovascular system and affect the contractile function of the myocardium.

To maintain a high energy reserve, doctors prescribe cardiac glycosides to treat chronic failure.

Glycoside group drugs increase the efficiency of the heart, improve blood flow and have a decongestant effect.

Cardiac glycosides are organic compounds derived from medicinal plants. They have a selective tonic effect on the myocardium. Plants are used in many recipes of traditional medicine, they are the main component of this pharmaceutical group.

The mechanism of action of cardiac glycosides is increased cardiac output. The drug shortens the period of contraction of the ventricles and lengthens their resting time.

As a result, systole becomes more pronounced, and the frequency of contractions decreases. In addition, glycosides act on the vagus nerve, increasing its tone, which affects the slowdown of the heart rhythm. Cardiac glycosides contribute to increased activity of the heart muscle, while energy costs remain negligible.

Glycosides have several main forms of exposure to the body:

  • inotropic effect (increase in myocardial ejection fraction);
  • chronotropic negative effect (slowing of the heart rhythm);
  • dromotropic property (retardation of atrioventricular conduction);
  • batmotropic effect (increased excitability of the heart).

Therefore, before making a cardiogram of the heart, it is necessary to notify the doctor about taking the drug from the glycoside group. Under their influence, the results of the study will be somewhat specific.

Cardiac glycosides, depending on the speed of response and the duration of the effect, are divided into three types:

  1. The first includes long-acting drugs, due to their enhanced ability to accumulate (cumulation). They begin to work after 8 hours after taking and after 90 minutes with intravenous administration. The duration of exposure reaches 3 weeks. Cardiac glycosides with a long-term effect include digitalis purpurea.
  2. The second has an average duration. With intravenous administration, the drugs begin to act after 15 minutes, and the effect lasts a couple of days. Drugs derived from rusty digitalis and adonis have an average duration of influence.
  3. The third is emergency medicine. Glycosides of this group are characterized by quick but short exposure. Their effect begins in 3-5 minutes and lasts up to two days. Quick help preparations are based on the strophanthus and lily of the valley.

In case of insufficiency, cardiac glycosides are classified, starting from the polarity that distributes the drug according to the form of application. Polar substances dissolve well in water, but very poorly in fats.

Therefore, they are administered intravenously. Non-polar, in turn, are well absorbed into the gastrointestinal tract and bind to proteins.

Therefore, non-polar substances can be safely taken in the form of tablets or medicines.

Each type of cardiac glycoside is used depending on the complexity of the disease. The dosage and duration of treatment is determined by the doctor individually.

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Drug List

For the manufacture of cardiac glycosides, plants are used that are distributed throughout Russia. Among them are digitalis (all varieties), May lily of the valley, spring adonis, Montenegrin, and jaundice.

The only foreign plant is the strophanthus, which is found mainly in Africa. Many drugs got their name, starting from the name of the plant that is part of them. Today, there are several hundred varieties of cardiac glycosides.

But only a couple of dozen, with well-studied pharmacological properties, took their place in practicing medicine:

  • Digitaloxin is based on digitalis purpurea (Digitalis) purpurea. Digoxin, Celanide, and Izolanide preparations were made from woolly digitalis. These drugs are made in the form of a solution for intravenous administration. The action of the drug is aimed at increasing the strength of myocardial contractions, lengthening diastole and lowering the heart’s oxygen demand. The drug is not advisable for use during pregnancy and with increased sensitivity to the components.

“Digitoxin” takes the first place in popularity of the appointment, since it practically does not cause any side effects.

It, like other drugs based on woolly digitalis, is prescribed much less often due to its high cumulative function.

At the same time, it becomes very difficult to guess the necessary dosage for the patient, which contributes to the occurrence of side effects (the most common is intoxication).

  • “Gomfokarpin” and “Gomfotin” are made from shrub harga (Gomphokarpus). The drugs are released in the form of tablets. The action is aimed at the general restoration of the myocardium.
  • “Periplocin” is a cardiac glycoside isolated from an entanglement (Periploca). The effect of the drug is associated with a decrease in heart rate and restoration of compensatory function. To treat heart failure, use an intravenous solution. The course is prescribed after a single use of Strofantin.
  • “Strophanthin” is made from the tropical plant strophanthus (Strophanthus). The medicine is released in the form of an injection. The work of the drug is the energy supply of the myocardium, which improves its functionality as a whole.
  • “Adoniside” is synthesized from spring adonis (Adonis vernalis). The drug has a cardiotonic effect on the myocardium (increases the strength of heart contractions). Take it inside in the form of a liquid. “Adoniside” is contraindicated in people with a problem gastrointestinal tract.
  • “Erysiminin” is made from the yellifer (Erysimum).
  • Korglikon is based on the May lily of the valley (Convallaria). The pharmacological action is aimed at reducing venous pressure and increasing urine output. With the help of Korglikon, shortness of breath and puffiness are relieved.

Large dosages of glycosides are immediately prescribed, then gradually the amount of drugs used is reduced or transferred to a less active form.

Particular care should be taken in calculating the required dose when administering to patients with overweight, due to the lack of cumulation of the substance in adipose tissue.

When choosing the quantity, an individual approach is necessary taking into account the weight, height and age of the patient.

Quick pharmacological assistance can be provided with the help of cardiac glycosides “Strofantin” and “Korglikon.” These are emergency medications, because their action begins very quickly and has a short duration.

A full course of treatment with such drugs is not carried out, but a gradual transition to drugs with a lasting effect is carried out. Often after “Strofantin” or “Korglikon”, “Periplocin” is prescribed, which after quick help has a restorative and supporting effect.

Противопоказания

Like other drugs, cardiac glycosides have a number of contraindications. They are prohibited when:

  • decreased heart rate (less than 60 per minute);
  • pathology of regular fainting (Morgagni Adams Stokes syndrome);
  • shock conditions and an attack of myocardial infarction (absolute contraindication);
  • tachycardia, sinus bradycardia and arrhythmia;
  • hypersensitivity to the components of a glycosidic drug;
  • weakened work of the gastrointestinal tract, problems with the kidneys and urinary function;
  • aortic valve insufficiency.

Side effect

With the right dosage, cardiac glycosides do not cause any adverse reactions. But if the doctor’s recommendations are exceeded, some systems and organs may be affected:

  1. An overdose of glycosides can cause nausea and vomiting. This is due to a change in the motility of the gastrointestinal tract under the influence of the drug.
  2. In large quantities, they negatively affect the nervous system, because of which depression and apathy can occur, a normal sleep abyss. Headaches appear, visual impairment is possible. In some cases, clouding of consciousness and the occurrence of hallucinations are noted. Failures in the nervous system can cause changes in the perception of the color palette of the surrounding world.
  3. A critical overdose sometimes causes ventricular flutter and cardiac arrest.
  4. With prolonged intake of cardiac glycosides, intoxication of the body may occur. Therefore, at the first signs it is necessary to take a break in treatment. The action of glycosides also contributes to the narrowing of blood vessels, which can cause an increase in arterial or venous pressure.

Any changes in the functionality of the body and well-being should be immediately reported to the attending physician.

Apricot kernels and bitter almonds also contain cardiac glycosides. But their extraction for the treatment of heart disease is prohibited. Under the influence of enzymes, hydrocyanic acid is produced from raw materials – a potent poison.

Only in very small doses can it have a healing effect. The lethal dose of poison is 0,05 g, while the dose of hydrocyanic acid in bitter almonds reaches 0,4 g.

This reason is the basis of the ban on the use of such raw materials for the extraction of cardiac glycosides.

Heart disease is a serious condition of the whole organism. Any violations of it can lead to death. At the slightest sign of the development of heart ailments, it is necessary to seek medical help. This will save you from developing serious illnesses and taking dangerous drugs.

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Sources of obtaining compounds with cardiotonic properties are medicinal plants from certain families. They are well studied by a science called pharmacognosy. The names of the drugs come from the plants from which they are isolated. For instance:

  • red (purple) type of digitalis (digitalis) – Digitaloxin, Cordigitum;
  • woolly type of digitalis – Digoxin, Celanide, Lantozide;
  • rusty digitalis – Digalen-neo;
  • adonis (Campion) – Adoniside;
  • strophanthus – Strofantin K, Strofantidin acetate;
  • lily of the valley – Korglikon;
  • icteric – Cardiovalen.

From a chemical point of view, cardiac glycosides are a combination of the following substances:

  1. Aglycon (genin) is a steroid structure similar in chemical structure to hormones, bile acids, sterols. It is genin that determines the magnitude and mechanism of the cardiotonic action of the drug.
  2. Sugar part (glycon) – can be represented by molecules of different sugars, it is responsible for the ability to dissolve and be fixed in tissues.

The duration of action and characteristics of the administration of these drugs depend on the chemical formula. Their classification is also based on this. Among cardiac glycosides, there are drugs that are better soluble in fats (Digoxin, Digitoxin, Celanide). They are well absorbed in the intestines and poorly excreted in the urine, therefore, are prescribed for oral administration.

On the contrary, agents that are highly soluble in water are poorly absorbed in the digestive tract, so they are best administered parenterally (Korglikon, Strofantin). They are well excreted through the kidneys, the duration of their action is small.

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The duration of glycosides is also affected by their ability to form bonds with blood plasma proteins and accumulate. The longest running Digitoxin (up to 2-3 weeks), the least Strofantin and Korglikon (2-3 days). Digoxin and Celanide have an average duration of action (average week).

Cardiac glycosides (SG) belong to the group of cardiotonic (enhancing contractile activity and increasing cardiac efficiency) drugs.

All SG are substances of plant origin. Now about 350 items with cardiotonic activity have been allocated, but only a few dozen are used in medicine. Synthetic glycosides are only limitedly used in some countries.

Classification of SG by origin:

  1. Digitalis drugs (Digitalis):
    1. Purple – Digitoxin (not used in recent years);
    2. Woolly – Digoxin, Celanide;
  2. Strophanthus Group:
    1. Strofantin K;
    2. Etrofantin G;
  3. May lily of the valley preparations (Convallaria majalis):
    1. Korglikon;
    2. Tincture of lily of the valley;
  4. Group of spring adonis (Adonis vernalis):
    1. Infusion of adonis herb.

Characteristics of SG by their pharmacokinetic qualities:

  1. Nonpolar – lipophilic (digitoxin). Almost completely adsorbed in the digestive tract, firmly bound to plasma albumin, are subject to enterohepatic circulation. They have a very pronounced cumulative effect. They begin to act in 1,5-2 hours, are eliminated from the body in 14-21 days
  2. Moderately polar (digoxin, celanide). They have good absorption, bind to proteins by 20-30%, are partially biotransformed by the liver, excreted in feces and urine. May accumulate in the body. The onset of action is after 30-120 minutes (with parenteral administration – 5-30 minutes), complete elimination is observed after 5-7 days.
  3. Polar (Strofantin, Korglikon). Poorly adsorbed in the gastrointestinal tract (intended primarily for intravenous administration), are not metabolized and excreted unchanged by the kidneys. They have cumulative (cumulative) abilities. The onset of action occurs in 5-10 minutes, elimination in 1-3 days.

Modern studies in pharmacognosy are aimed at developing chemical methods for the transformation of natural glycosides into preparations with improved pharmacotherapeutic properties, cultivating plants with a high content of SG by agrotechnical methods, and searching for new methods for obtaining raw materials for drugs.

List of preparations from cardiac glycosides of plant origin:

  • Strophanthin;
  • Digoxin;
  • Digitoxin;
  • Korglikon;
  • Celanide;
  • Adoniside.

Also in clinical practice, semi-synthetic hypertension is used – methylazide, acetyldigoxin.

The drugs are available in the form of tablets or in ampoules for intravenous administration.

84. Combined antibiotic therapy. Rational combinations.

Indications for
combination antibiotic therapy.

treatment of severe
patients with suspected infection
of unknown origin

warning
development of resistant strains in
some clinical situations

spectrum expansion
antimicrobial activity (therapy
mixed infections)

gain
antimicrobial effects in severe
states

toxicity reduction
individual batteries

Principles
combination antibiotic therapy.

1. Cannot be combined
bactericidal and bacteriostatic
AB

2. It is impossible together
use AB with similar side effects
effects.

3. Not recommended
use at the same time more
two or three AB

4. Combined
antibiotic therapy should be convenient
for the patient and possibly economically
profitable

Mechanism of action

Cardiac glycosides are complex nitrogen-free compounds of plant origin with a selective cardiotonic effect (they can increase myocardial contractility, stroke and minute blood volume without increasing oxygen consumption).

The glycoside molecule consists of two parts:

  1. Glycon – sugar, which determines the pharmacokinetics of the drug (the ability to dissolve in water, fats, acids, passage through the cell membrane, absorption rate in the digestive tract, bond strength with plasma proteins, relationship with receptors).
  2. Aglycon – a structure that is responsible for the mechanism of action and pharmacodynamics (directly the clinical effects of taking the substance).

The cardiotonic mechanism of action of cardiac glycosides is associated with the ability:

  • inhibit the activity of Na-K-ATPase (the enzyme responsible for the sodium-potassium pump), reducing cell repolarization;
  • forming complexes with Ca 2 ions to transport them inside a cardiomyocyte;
  • stimulate the release of ions from the sarcoplasmic reticulum into the free cytoplasm.

As a result of these processes, the concentration of functionally active Ca2 inside the cardiomyocyte increases. This ion provides the neutralization of the troponin-tropomyosin complex and the release of the actin protein, which interacts with myosin, forming the basis of the heartbeat. In addition, Ca2 ions activate the myosin ATPase, which supplies the contractile process with the necessary energy.

The effect of Ca2 ions on cardiac activity:

  • Increased heart rate;
  • Acceleration of heart rate
  • Increased myocardial excitability and pacemaker automatism.

Therefore, under the action of cardiac glycosides, the work of the heart becomes more economical, as they optimize the use of ATP and the need for oxygen.

Pharmacological effects of taking glycosides:

  1. Positive inotropic effect. The strength of myocardial contractions increases, systole is shortened, as a result of which the stroke volume of the blood and cardiac output return to normal. Partly due to the release of catecholamines and increased tone of the sympathetic nervous system.
  2. Negative chronotropic effect. Elongation of diastole (myocardial rest time and filling the coronary vessels with blood) and a decrease in heart rate.
  3. Negative dromotropic effect. Slowing the passage of the pulse along the conduction system of the heart (from the sinus to the atrioventricular node).
  4. Diuretic action. In patients with decompensated heart failure and fluid retention in the body due to improved renal circulation and inhibition of reabsorption of Na ions in the distal tubules, daily diuresis increases.
  5. Sedative effect.
  6. Strengthening intestinal motility, gall bladder tone.

Hemodynamic effects of cardiac glycosides:

  • Strengthening and shortening the duration of systole;
  • Increase in minute blood volume, ejection fraction of the left ventricle;
  • Lengthening diastole;
  • Heart rate reduction (effect on the vagus nerve);
  • Approaching the normal size of the heart;
  • Decrease in venous pressure;
  • Optimization of the blood supply to the heart muscle (improvement of subendocardial blood flow, rheological properties of blood);
  • Decreased circulating blood volume, oxygen consumption by the myocardium;
  • Normalization of pressure in the vessels of the small circle, reducing the risk of pulmonary edema, improving gas exchange, oxygen saturation of the blood;
  • Elimination of edema.

85. Sulfanilamide preparations.

Classification
sulfonamide preparations for
resorptive action on his
duration.

a) short
action (T1 / 2

10 h): sulfonamide
(streptocide)

sulfadimidine
(sulfadimesin), sulfaethidol (ethazole).

b) average
duration of action (T1 / 2
10-24 h):
sulfadiazine.

c) long
action (T1 / 2
24-48 hours):
sulfamethoxypyridazine,
sulfadimethoxin, sulfadoxine

d) super long
action (T1 / 2
60
hours): sulfalene.

Features
therapeutic effect of drugs
sulfonamides combined with
salicylic acid.

These drugs are more
effective in inflammatory diseases
intestines: sulfasalazine
digested by intestinal microflora with
sulfapyridine release
and 5-aminosalicylic acid;
5-aminosalicylic
acid in
intestinal lumen creates high
concentration and exerts its main
anti-inflammatory effect)

Indications for
the use of sulfasalazine.

non-specific
ulcerative colitis

Mechanism
antimicrobial action of sulfonamide
preparations.

For
education vital
folic acid (which is involved in
nucleic acid synthesis) microorganisms
need extracellular para-aminobenzoic
acid (PABA). Sulfonamides compete
with PABA for the enzyme dihydropteroate synthetase,
leading to the formation of non-functional
folic acid analogues.

Antibacterial
spectrum of sulfonamides.

Initially to
sulfonamides were sensitive
many gram-positive and gram-negative
cocci, gram-negative sticks, however
they have currently acquired
sustainability.

Sulfanilamides
remain active against nocardia,
toxoplasma, chlamydia, malaria
plasmodium.

Complications of Therapy
sulfonamides.

a) crystalluria
with an acid reaction of urine

b) jade
hypersensitive nature

2. Dyspeptic
phenomena (nausea, vomiting, diarrhea)

3. Skin reactions
(rash, exfoliative dermatitis)

4. Neurological
reaction

6. Violations of hematopoiesis
(anemia, leukopenia)

Precautionary measures,
necessary for sulfanilamide therapy.

1. For warning
crystalluria patients when taken
sulfa drugs should
getting plenty of alkaline drink.

2. The correct choice
drug (when using drugs
long-acting side effects
usually less pronounced that
due to the intake of these drugs in
lower doses)

NB!
However, it should be borne in mind that in connection with
slow excretion from the body and
the possibility of cumulation, side effects
long-acting sulfonamides
may be more persistent than when taken
sulfonamide drugs short
actions.

3. Careful
compliance with the dosage regimen

Chemically they
are sulfanilamide derivatives
(sulfanilic acid amide).

Sulfanilamides
may be represented by the following
in groups.

Drugs
used for resorptive action
(well absorbed from the gastrointestinal
tract) A. Middle
duration of action of sulfadimezin
Ethazole Sulfazine Urosulfan B. Prolonged
action of sulfapyridazine sulfadimethoxine
B. Super Long-Term Sulfalen

Drugs
acting in the intestinal lumen (poor
absorbed from the gastrointestinal
tract) Phthalazole

Preparations
for topical use Sulfacyl sodium
Sulfazine Silver Salt

a) bacteria –
pathogenic cocci (gram-positive and
gram-negative), E. coli,
causative agents of dysentery (shigella),
cholera vibrio, gas pathogens
gangrene (clostridia), pathogens
anthrax, diphtheria, catarrhal
pneumonia, influenza;

b) chlamydia –
causative agents of trachoma, ornithosis, inguinal
lymphogranulomas;

d)
protozoa – the causative agent of toxoplasmosis,
plasmodium malaria. Especially active
Sulfonamides against pneumococci,
menococcus, gonococcus, some
types of hemolytic streptococci, and
also bacterial pathogens
dysentery.

Antimicrobial mechanism
the action of sulfonamides is associated with their
competitive antagonism with
para-aminobenzoic acid. Preparations
this group is quickly and completely absorbed
from the gastrointestinal tract.

From sulfonamides
medium duration
sulfadimesin is most commonly used,
etazole, sulfazine, urosulfan. To this
the same group includes streptocide.

К
long-acting drugs
include sulfapyridazine and sulfadimethoxine
(madribon, madroxin). They are good
absorbed from the gastrointestinal
tract, but slowly stand out.

Drug
oversight
is sulfalene which in
bacteriostatic concentrations
lingers in the body for up to 1 week.

Antimicrobial
sulfonamides activity significantly
inferior to antibiotics, therefore the scope
Their application is quite limited. Them
prescribed mainly with
antibiotic intolerance or
developing addiction to them. Often
sulfonamides are combined with some
antibiotics.

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Supfanilamides
apply for resorptive action
with coccal infections, especially with
meningococcal meningitis, diseases
respiratory tract infection
and biliary tract, etc.

Presents
interest combination sulfanilamides with
drugs that, oppressing
dihydrofolate reductase block
dihydrofolic acid transition to
tetrahydrofolic acid. To such
substances include trimethoprim.

Inhibitory effect
a similar combination manifesting on
two different stages, essentially
increases antimicrobial activity –
the effect becomes bactericidal.

The drug is produced
bactrim containing trimethoprim and
sulfamethoxazole. He has a high
antibacterial activity.
It has a bactericidal effect.
Well absorbed from the gastrointestinal
tract.

Bactrim is contraindicated
with severe dysfunctions
liver, kidney and blood formation. Do not do it
appoint it to children under 6 years old and at
pregnancy.

Sulfadimidine,
sulfadiazine, sulfadimethoxine,
co-trimoxazole, phthalylsulfathiazole
(phthalazole), sulfacetamide, sulfasalazine.

SULFADIMESIN
(Sulfadimezinum). 2- (para-Aminobenzenesulfamido)
– 4, 6 – dimethylpyrimidine.

Synonyms: Diazil,
Diazol, Dimethazil, Dimethyldebenal, Dimethylsulphadiazine,
Dimethylsulphapyrimidine, Pirmazin, Sulfadimerazine, Sulfadimidine,
Sulfadimidinum, Sulfamethazine, Sulfamezathil, Sulfamezathine,
Sulmet, Sulphadimethylpyrimidine, Sulphadimidine, Superseptyl.

Apply with
pneumococcal, streptococcal,
meningococcal infections, sepsis,
gonorrhea, as well as infections caused by
Escherichia coli and other microorganisms.

Sulfadimezin
rapidly absorbed, relatively
low toxicity.

Doses
for adults, the same as the dose
norsulfazole.

Sulfadimesin like
and other sulfa drugs
often used with antibiotics.

В
combined with chloridine sulfadimezin
used for toxoplasmosis.

RџSЂRё
treatment with sulfadimezin prescribed
heavy alkaline drink. Necessary
systematically conduct research
blood, as in the treatment of others
sulfa drugs.

SULFAZIN
(Sulfazinum). 2- (para-Aminobenzenesulfamido)
pyrimidine.

Synonyms:
Adiazin, Debenal, Pirimal, Pyrimal, Sulfadiazin, Sulfadiazinum,
Sulfapyrimidin, Ultradiazin and
др.

Sulfazine less
binds to plasma proteins and slower
excreted from the body than norsulfazole,
which provides higher
blood sulfazine concentration and
bodies.

Indications for
the applications are the same as for norsulfazole.

With dysentery
prescribed as sulfadimezin
(cm).

Sulfazine often
used together with other sulfonamide
drugs. In combination with antimalarial
means (quinine, chloridine, etc.)
sulfazine is used in the treatment
drug-resistant forms of malaria.
Sulfazine is active against asexuals
erythrocyte stages of malaria
plasmodium. Like antimalarial
sulfazine (like others
sulfonamide preparations) relatively
little active, developing rapidly for him
plasmodium resistance.

Sulfazine relatively
rarely causes nausea and vomiting; and
changes in the hematopoietic system. Sometimes
hematuria, oliguria, anuria are observed.

RџSЂRё
sulfazine treatment is necessary
maintain enhanced diuresis, profuse
alkaline drink can prevent
the development of impaired renal function.

SULFAZINA
SILVER SALT (Sulfazini argenti).

Differs from
other sulfa drugs
the presence of a silver atom in the molecule, which
strengthens its local antimicrobial –
bactericidal – action.

RџSЂRё
topical application in the form of ointments for wound
surface occurs gradual
silver ion release that
provides long-term action
drug.

Ointment
applied to the affected surface
(after surgical treatment and removal
necrotic tissue) with a thin layer
(under a blindfold or in an open way).
The dressing is changed 1 to 2 times a day or less.
Duration of treatment is up to 3 weeks.

Properties and indications for use

Indications for the use of SG:

  1. Acute and chronic heart failure due to impaired contractility. (Most often, glycosides are prescribed to patients with congestive heart failure II, III, or IV functional class).
  2. Atrial fibrillation (tachysystolic form);
  3. Paroxysmal, supraventricular, atrial tachycardia;
  4. Vegetative-vascular cardioneurosis.

The list of contraindications for the use of cardiac glycosides:

  • Severe bradycardia;
  • Atrioventricular block II-III degree;
  • Morgagni-Adams-Stokes Syndrome, WPW;
  • Polytopic extrasystole;
  • Heart failure with diastolic dysfunction;
  • Acute coronary syndrome;
  • Sick sinus syndrome (without an established pacemaker);
  • Infectious myocarditis;
  • Constrictive pericarditis;
  • Ventricular tachycardia;
  • Electrolyte imbalance: hypokalemia, hypercalcemia;
  • Mitral valve stenosis;
  • Hypertrophic cardiomyopathy (obstructive form);
  • Thoracic aortic aneurysm;
  • Hypertrophic subaortic stenosis;
  • Heart tamponade;
  • Carotid sinus syndrome;
  • Restrictive cardiomyopathy;
  • Arrhythmias caused by a history of glycoside intoxication;
  • Chronic renal failure with programmed hemodialysis;
  • Hypersensitivity to any cardiac glycosides.

These drugs require individual dose selection (for long-term therapy, it is titrated for 7-10 days) and regular monitoring of the patient’s clinical condition (ECG, blood electrolytes – K, Ca, Mg).

If intravenous administration is necessary, the dose of the drug is divided into 2-3 doses.

Dose adjustment is required for patients with:

  1. Thyroid disease. With hypothyroidism, the dose of cardiac glycosides must be reduced. In the case of thyrotoxicosis, relative resistance to hypertension is observed.
  2. Malabsorption syndrome, short bowel. Due to malabsorption of the drug, an increase in dose is required.
  3. Severe respiratory disease (increased sensitivity to glycosides).
  4. Electrolyte imbalance. High risk of digital intoxication and arrhythmia.

In elderly patients and debilitated patients, the drug withdrawal period is extended, which increases the risk of side effects and overdose.

The interaction of glycosides with other medicinal substances, requiring dose adjustment:

  1. Adrenomimetics – Epinephrine, selective β-agonists (incompatible, risk of arrhythmias);
  2. Aminazine reduces the effectiveness of SG;
  3. Anticholinesterase drugs – Proserin, Physiostigmine (increase bradycardia);
  4. Glucocorticosteroids – Hydrocortisone, Prednisone (increase the frequency of side effects);
  5. Diuretics – Furosemide, Trifas (enhance the effect of SG);
  6. Paracetamol (decreased urinary glycoside excretion);
  7. β-blockers and antagonists of Ca 2 channels (the occurrence of bradycardia and complete heart block).

Cardiac glycosides have two types of pharmacological effects:

  1. Cardiac – an increase in contractile activity of the myocardium, a decrease in conduction and heart rate (HR), an increase in the excitability of the heart muscle. In addition, they contribute to an increase in the duration of diastole – the period when the heart rests and accumulates energy reserves.
  2. Extracardial phenomena – narrowing of peripheral vessels, diuretic and sedative effect.

The implementation of the main mechanism of action of cardiac glycosides (an increase in the strength of systolic contractions) leads to an increase in indicators such as stroke and minute blood volume, to a decrease in the anatomical size of the heart, lower venous pressure, and elimination of edematous syndrome. It is important that the oxygen consumption of the myocardium does not increase.

The drugs of this group equally increase myocardial contractility both in the presence and in the absence of signs of functional heart failure. But in healthy people there is no increase in minute release. The degree of exposure depends not only on the dose of the drug, but also on the individual sensitivity of the body of a particular person.

Due to the high risk of side effects and the presence of contraindications for use, the group of cardiac glycosides is a potentially dangerous drug, so only a specialist can treat them.

The following pathological conditions become indications for the appointment of cardiac glycosides:

  • heart failure – acute and chronic;
  • supraventricular arrhythmias (tachycardia), including with a paroxysmal course;
  • atrial fibrillation;
  • atrial fibrillation attacks;
  • pericardial tamponade of the heart (compression).

Contraindications for the appointment of these drugs:

  1. Cardiac glycosides can not be treated with bradycardia, atrioventricular blockade of varying degrees, unstable angina.
  2. It is forbidden to prescribe these drugs during acute inflammatory processes (myocarditis), in fainting conditions caused by heart rhythm disturbances (attacks of Morgagni-Adams-Stokes).
  3. An absolute contraindication is a history of intolerance to digitalis and other cardiotonic plants.
  4. You can not continue treatment with cardiac glycosides with severe symptoms of intoxication.

Side effects and overdose symptoms

During treatment with cardiac glycosides, like any other medication, there is a risk of adverse reactions:

  1. Rhythm and conduction disturbances (sinus bradycardia, blockade, ventricular fibrillation);
  2. Violations of the blood system – eosinophilia, thrombocytopenia, agranulocytosis;
  3. Allergic manifestations – skin itching, hyperemia, rashes (erythematous, papular), urticaria, Quincke’s edema.
  4. Gynecomastia (breast enlargement) in men due to estrogenic activity of hypertension;
  5. Mental disorders – depression, auditory and visual hallucinations, memory disorders, confusion;
  6. Neurological symptoms – migraines, asthenia, vertigo, sleep disturbance, nightmares, apathy or nervous agitation, myalgia;
  7. Blurred vision (the result of retrobulbar neuritis), photophobia, the effect of glow around objects, impaired color perception (seeing everything in the yellow-green or gray-blue range);
  8. Lack of appetite, abdominal pain, nausea, insufficiency of visceral blood flow, intestinal ischemia.

If the recommended doses are exceeded, SGs show their toxicity and are capable of disrupting metabolic processes, causing a delay in Ca2 in the cytoplasm due to problems with its elimination from the cell. At the same time, the amount of ATP, glycogen, proteins, potassium, magnesium decreases and the metabolism shifts to the anaerobic side. Myocardial relaxation in the diastole is impaired, the stroke volume of the blood drops, the pre- and afterload increases.

Non-compliance with the rules of treatment with glycosides (self-increasing the dose or shortening the intervals between doses) is fraught with the development of overdose symptoms:

  • Arrhythmias, bradycardia, AV blockade, extrasystoles, ventricular fibrillation;
  • Nausea, diarrhea, lack of appetite, feeling of full stomach;
  • Headaches, vertigo, psychomotor agitation;
  • Decreased visual acuity, violation of color perception, scotomas (blind spots), distortion of the size of the subject;
  • Impaired consciousness, syncope.

In case of overdose symptoms, the following measures must be taken:

  • stop taking glycosides immediately;
  • Induce vomiting, rinse stomach;
  • Take activated charcoal (at the rate of 1 tablet per 10 kg of weight) or another sorbent;
  • Seek medical attention immediately.

In a hospital, a patient with an overdose of cardiac glycosides is administered:

    Subcutaneous administration of Unithiol (ant >

The mechanism of action of Unithiol (universal antidote) is associated with the property to reduce the toxic effect of glycosides on the functional activity of ATPase and normalize energy metabolism in the myocardium.

Given the frequency of side effects, overdose and their relationship with a violation of the scheme of application of cardiac glycosides, the doctor should focus the patient on strict adherence to prescriptions, and the patient must definitely study the instructions for the drug before using it. It is strictly forbidden to replace the glycoside with an analog on its own without prior coordination with your doctor.

conclusions

Glycosides are drugs for the treatment of chronic heart failure with impaired contractile function. A particularly good effect is observed in patients with a combination of heart failure and atrial fibrillation. In this case, a slow digitalization scheme is shown.

Prescribing cardiac glycosides (most often Digoxin) to patients improves the course of the disease, quality of life, and increases resistance to physical activity, without changing the oxygen demand of the myocardium. Against the background of taking SG in patients, weakness, shortness of breath, sleep improves, edema, cyanosis disappear, tachycardia goes into a normal rhythm, diuresis increases, ECG indicators stabilize.

Tatyana Jakowenko

Editor-in-chief of the Detonic online magazine, cardiologist Yakovenko-Plahotnaya Tatyana. Author of more than 950 scientific articles, including in foreign medical journals. He has been working as a cardiologist in a clinical hospital for over 12 years. He owns modern methods of diagnosis and treatment of cardiovascular diseases and implements them in his professional activities. For example, it uses methods of resuscitation of the heart, decoding of ECG, functional tests, cyclic ergometry and knows echocardiography very well.

For 10 years, she has been an active participant in numerous medical symposia and workshops for doctors - families, therapists and cardiologists. He has many publications on a healthy lifestyle, diagnosis and treatment of heart and vascular diseases.

He regularly monitors new publications of European and American cardiology journals, writes scientific articles, prepares reports at scientific conferences and participates in European cardiology congresses.

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