Foxglove - medicinal properties in traditional medicine recipes. Medicinal properties of foxglove and other advantages of the plant How to prepare medicinal raw materials from foxglove

Facilities. More than 200 years ago it was found that they selectively affect the heart, enhancing its activity, normalizing blood circulation, which ensures an anti-edematous effect.

The pharmacodynamic effects of cardiac glycosides are due to their effect on the cardiovascular, nervous systems, kidneys and other organs.

The mechanism of cardiotonic action is associated with the influence of cardiac glycosides on metabolic processes in the myocardium. They interact with the sulfhydryl groups of the transport Na + , K + -ATPase of the cardiomyocyte membrane, reducing the activity of the enzyme. The ion balance in the myocardium changes: the intracellular content of potassium ions decreases and the concentration of sodium ions in the myofibrils increases. This helps to increase the content of free calcium ions in the myocardium by releasing them from the sarcoplasmic reticulum and increasing the exchange of sodium ions with extracellular calcium ions. An increase in the content of free calcium ions in myofibrils promotes the formation of a contractile protein (actomyosin), necessary for cardiac contraction. Cardiac glycosides normalize metabolic processes and energy metabolism in the heart muscle, increase the conjugacy of oxidative phosphorylation. As a result, systole significantly increases.

Increased systole leads to an increase in stroke volume, more blood is ejected from the heart cavity into the aorta, blood pressure increases, presso- and baroreceptors are irritated, the center of the vagus nerve is reflexively excited and the rhythm of cardiac activity slows down. An important property of cardiac glycosides is their ability to lengthen diastole - it becomes longer, which creates conditions for rest and nutrition of the myocardium, and restoration of energy costs.

Cardiac glycosides are able to inhibit the conduction of impulses through the conduction system of the heart, as a result of which the interval between contractions of the atria and ventricles is prolonged. By eliminating reflex tachycardia resulting from insufficient blood circulation (Weinbridge reflex), cardiac glycosides also contribute to prolongation of diastole. In large doses, glycosides increase cardiac automaticity and can cause the formation of heterotopic foci of excitation and arrhythmia. Cardiac glycosides normalize hemodynamic parameters characterizing heart failure, while congestion is eliminated: tachycardia, shortness of breath disappear, cyanosis decreases, and edema is relieved. diuresis increases.

Some cardiac glycosides have a sedative effect on the central nervous system (glycosides of adonis, lily of the valley). The diuretic effect of cardiac glycosides is mainly due to the improvement of heart function, but their direct stimulating effect on kidney function is also important.

The main indications for the use of cardiac glycosides are acute and chronic heart failure, atrial fibrillation and flutter, and paroxysmal tachycardia. An absolute contraindication is intoxication with glycosides.

With long-term administration of glycosides, an overdose is possible (given the slow elimination and ability to cumulate). accompanied by the following symptoms. From the gastrointestinal tract - epigastric pain, nausea, vomiting: cardiac symptoms - bradycardia, tachyarrhythmia, atrioventricular conduction disturbance; heartache; in severe cases - dysfunction of the visual analyzer (impaired color vision - xanthopsia, macropsia, micropsia). Diuresis decreases, the functions of the nervous system are disrupted (excitement, hallucinations, etc.). Treatment of intoxication begins with withdrawal of the glycoside. Potassium preparations are prescribed (potassium chloride, panangin, potassium orotate), since glycosides reduce the content of potassium ions in the heart muscle. Unithiol and diphenin are used as antagonists of cardiac glycosides in their effect on transport ATPase in complex therapy. Since cardiac glycosides increase the amount of calcium ions in the myocardium, drugs that bind these ions can be prescribed: disodium ethylene diamine tetraacetic acid or citrates. To eliminate emerging arrhythmias, lidocaine, diphenine, propranolol and other antiarrhythmic drugs are used.

In medical practice, various preparations from plants containing cardiac glycosides are used: galenic, neogalenic, but most widely - chemically pure glycosides, for which there is no need for biological standardization. Cardiac glycosides obtained from different plants differ from each other in pharmacodynamics and pharmacokinetics (absorption, ability to bind to blood plasma and myocardial proteins, rate of neutralization and excretion from the body).

One of the main glycosides of digitalis (purpurea) is digitoxin. Its action begins after 2-3 hours, the maximum effect is achieved after 8-12 hours and lasts up to 2-3 weeks. With repeated use, digitoxin is capable of accumulation (cumulation). Glycoside isolated from foxglove woolly digoxin, which acts faster and for less time (up to 2-4 days), accumulates in the body to a lesser extent compared to digitoxin. Even faster and shorter action celanidae (isolanide, also obtained from foxglove woolly. Because digitalis preparations act relatively slowly. but long-term, it is advisable to use them for the treatment of chronic heart failure, as well as for cardiac arrhythmias. Celanide, given its pharmacokinetics, can be prescribed intravenously for acute heart failure.

Preparations of spring adonis ( adonizide) dissolve in lipids and in water, are not completely absorbed from the gastrointestinal tract, have less activity, act faster (after 2-4 hours) and shorter - (1-2 days), since they bind to blood proteins to a lesser extent. Given the pronounced calming effect, adonis preparations are prescribed for neuroses, increased excitability ( Bekhterev's medicine).

Strophanthus preparations are very soluble in water, poorly absorbed from the gastrointestinal tract, so taking them orally gives a weak, unreliable effect. They bind loosely to blood plasma proteins, and the concentration of free glycosides in the blood is very high. When administered parenterally, they act quickly and powerfully and do not linger in the body. Strophanthus glycoside strophanthin usually administered intravenously (subcutaneous and intramuscular administration is possible). The effect is observed after 5-10 minutes, the duration of the effect is up to 2 days. Strophanthin is used for acute heart failure that occurs due to decompensated heart defects, myocardial infarction, infections, intoxications, etc.

Lily of the valley preparations are close to strophanthus preparations in pharmacodynamics and pharmacokinetics. Korglykon contains the sum of lily of the valley glycosides, is used intravenously for acute heart failure (as strophanthin). Galenic drug - tincture of lily of the valley when taken orally, has a slight stimulating effect on the heart and a sedative effect on the central nervous system, may increase activity and toxicity

Foxglove flowers are not only extremely beautiful, but also have medicinal properties. But treatment with digitalis must be careful, because in large doses it is a powerful poison.

A medicinal plant such as digitalis has found its application in a variety of fields. For its aesthetic appearance, the flower is used as a decorative element, and in medicine it is even magic remedy. However, improper use of this plant can cause great harm.

Description of foxglove, varieties, legends

Digitalis is a medicinal plant that is shrouded in doubts, myths and legends. It is a herbaceous plant with flowers that are shaped like fingers, hence the name - foxglove (thimble). Foxglove flowers come in a variety of colors, from bright yellow to brown.

There are several varieties of this plant - foxglove purpurea, foxglove woolly, foxglove grandiflora, etc. Refers to the plantain family and has a strong effect on the human cardiovascular system.

Actively used since ancient times for the treatment of heart diseases, if the dose is incorrectly selected, it can cause poisoning or even death.

Foxglove is used not only for medicinal purposes; some of its varieties are used as an ornamental plant with beautiful large bell flowers, and in their natural environment, foxglove bells are home to insects or small rodents, and food for butterflies.

There are many legends and beliefs about these plants. In some cultures, foxglove is called "Witch's Thimbles" and they believe that this plant can protect from troubles, give good luck and health. But if you use foxglove with malicious intent, you can use this plant suppress a person's will and send troubles upon him. In fairy tales, it is believed that foxglove flowers are nothing more than the hats of good fairy-tale elves.

Chemical composition of foxglove

The leaves and flowers of foxglove contain so-called glycosides- substances that affect cardiac activity. Moreover, the amount and composition of these substances depends on the type of foxglove:

In Foxglove purpurea or Digitalise contains more than 62 glycosides, including acetyldigoxin, digoxin and gitoxin. Foxglove purpurea also contains choline, flavonoids and other healing substances. These chemicals strengthens the work of the heart for heart failure and other diseases of the heart, blood vessels, kidneys, eyes. In medicinal doses they are irreplaceable medicines, but you should also know that these substances in the body can accumulate and cause poisoning

In large doses, glycosides act as a strong poison, leading to severe poisoning of the body or even death. Therefore, under no circumstances should you take digitalis preparations on your own. Prescribes and controls the intake of glycosides exclusively doctor

Foxglove contains a large amount of steroid and cardiotonic glycosides, lantosides, celanides. Substances of this type of foxglove are eliminated from the body faster and accumulate less, so they are used more often. They fight congestive heart failure better and remove excess fluid from the body faster
Foxglove rusty contains more than 31 glycosides, verodoxin, steroids, flavonoids. It is used to treat heart disease and also to treat epilepsy

Digitalis, medicinal properties

Great Patriotic doctor and scientist Botkin said about foxglove: “This is the scalpel of therapists” and he was completely right. This plant has the strongest healing properties, but at the same time, it can cause harm if used incorrectly.

Digitalis and the preparations that are made from it have wide spectrum of action on the human body. They are used for:

Heart diseases

Heart failure – when the heart cannot provide adequate blood supply to the entire body, digitalis preparations increase the ejection of blood by the heart, thereby helping to fight heart failure
Arrhythmias and increased heart rate - influencing the heart rate regulation centers, restore it, and also slow down the pulse
Heart defects (congenital and acquired)

Vascular diseases:

Hypertension - reduce blood pressure

Eye diseases

Pain in the eyes migraines are well relieved with digitalis preparations
Increased intraocular pressure , for example, with glaucoma

Kidney diseases

For chronic renal failure
For swelling – help remove excess fluid from the body

For lung diseases- reduce shortness of breath and increase oxygen saturation of the body

Contraindications for taking digitalis

For taking digitalis preparations there is many contraindications. Before you start taking digitalis medicine, be sure to consult your doctor.

Taking digitalis and its medications without a doctor's advice is extremely life-threatening

It is not recommended to use medications containing digitalis extracts if you have:

Atherosclerosis of the coronary arteries
Myocardial infarction
Complete atrioventricular block
Decreased heart rate (bradycardia)
Rheumatic carditis or endocarditis
Heart defects in the compensation stage
Chronic lung diseases
Tuberculosis
Angina pectoris
Infectious diseases
Pregnancy
Breastfeeding period
Digitalis preparations are also not recommended for use in children under 12 years of age.

Is foxglove poisonous or not?

As mentioned above, digitalis preparations have many healing properties, but if you take them without control and incorrectly, you can get poisoning, the so-called "digitalis intoxication".

The fact is that cardiac glycosides, contained in digitalis, tend to accumulate in the body (cumulation effect). When they accumulate in excessive quantities, they begin act like poison. Here are the symptoms of digitalis intoxication:

Intense abdominal pain and diarrhea
Nausea and vomiting
Skin rash
Interruptions in heart function, sensation « heart sinking"
Rare and weak pulse
Shortness of breath, breathing problems
Muscle twitching and cramps
Hallucinations
Loss of appetite
Critical manifestation - respiratory and cardiac arrest

There are cases in history when digitalis tincture was used in large doses as a poison. Therefore, when using digitalis-based medications, be sure to follow all the recommendations of your doctor.

Tincture of foxglove woolly

Drugs woolly foxglove contain the same active substances as other types - cardiac glycosides. They have a stimulating effect on the cardiovascular system.

The tincture of foxglove woolly differs from foxglove purpurea by more rapid absorption in the body, quick effect and less ability to accumulate. Therefore, these drugs are preferred.

Tincture of foxglove woolly prepared at the rate of 1 g of dry leaves per 200 ml of water. It is best to buy a ready-made tincture at a pharmacy as prescribed by a doctor.

Video: Foxglove woolly

Digitalis preparations in the pharmacy

Many industrial preparations are made from foxglove leaves in various forms of release - tablets, injection solutions, tinctures, capsules, etc. The main preparations of digitalis purpurea are: digitoxin, gitoxin, cordigitite.

Digitoxin- pills. Used for heart failure, hypertension, heart valve defects, arrhythmias. Has a pronounced cumulation effect and is poorly soluble
Gitoxin- has the same therapeutic effect as digitoxin, but is much better dissolved in the body and less capable of accumulation. Available in white powder form
Cordigitate– a combination drug containing digitoxin and gitoxin. Available in the form of tablets and rectal suppositories. Easily soluble in water, the accumulation effect is very low

Digoxin is one of the digitalis-based drugs

The main dosage forms of foxglove woolly:

Digoxin– available in the form of tablets, solutions for intravenous injection and solution for oral administration. Prescribed for heart valve defects, arrhythmias, and before surgery for patients with chronic heart disease. If necessary, this drug can be prescribed to children. The effect comes faster, the ability to accumulate is very low
Celanide- Available in tablets and injection solutions. Indications for use are the same as for other digitalis preparations, but this drug has the widest spectrum of action and less toxic effects. The ability to cumulate is very little expressed
Lantoside- Available in 15 ml dropper bottles. This drug consists of several components of digitalis and has a pronounced anti-edematous effect. The ability to accumulate is poorly expressed

Video: Digoxin. Instructions for use

Foxglove tincture - instructions for use

It should be recalled once again that you only need to take digitalis as prescribed by a doctor and under his strict control, strictly following all recommendations. Only the doctor calculates the exact doses, time and frequency of administration.

200 ml of digitalis tincture contains from 0.5 to 1 g of dry leaves of the plant. Typically, adults take 20 ml 3-4 times a day.

Foxglove tincture is very easy to prepare - all you need is the flowers of the plant and alcohol

The duration of the course of treatment will also be determined strictly by the doctor. No way do not cancel or extend the course on one's own.

The use of digitalis for cardiac disorders

Used for heart diseases prepared preparations of digitalis. Taking homemade infusions is dangerous. The maximum amount of the drug per day should not exceed 0.5 g. The route of administration of the drug is also chosen by the doctor (tablets, intravenous injections) in each case individually.

The use of digitalis for edema

Since the substances contained in digitalis increase urine output they are used in the treatment of edema of cardiac origin. With the help of digitalis preparations, edema is treated as part of the treatment of heart failure.

Due to the increase in the amount of urine excreted, excess fluid is removed from the body and the load on the heart is relieved.

Use of digitalis for hypertension

For hypertension, use digitalis infusion. For 200 g of boiled warm water, take 1 g of dried foxglove leaves. Leave for 20-30 minutes. Take 1 tbsp. spoon 3-4 times a day. You should take digitalis tincture for hypertension only with the permission of your doctor.

Using digitalis for wound healing

Foxglove tincture lotions are used to heal wounds. Apply gauze soaked in the solution to the affected area and leave for 10-15 minutes.

Use of digitalis for nervous disorders

For diseases of the nervous system, digitalis alcohol tincture is used:

15-20 g dry leaves foxgloves pour 50 ml of alcohol
then placed in a dark glass container and allowed to brew for 7-10 days
use no more than 10 drops of infusion at a time

Recent studies have proven that digitalis preparations can be used in the treatment of epilepsy, hysteria and other mental disorders. Also, digitalis infusion is effective for migraine attacks with eye pain.

As you can see, foxglove is truly a magical remedy for many ailments, but it should be used wisely. Otherwise, you will cause serious harm to your body, even fatal outcome.

Video: Foxglove

Foxglove (Digitalis) is a herb of the plantain family. Distributed in the Mediterranean, found in Asia and northern Africa.

Chemical composition of foxglove

The composition of digitalis is replete with residues of organic compounds, which, in interaction with carbohydrates, form glycosides. The plant contains five such compounds: digitoxigenin, gitoxigenin, gitaloxygenin, digoxigenin and diginatigenin.

The glycosides present in digitalis are called cardenolides or cardiac glycosides (cardiotonic glycosides). The main ones are lanatosides A, B, C.

During chemical reactions, interaction with water, glycosides form new compounds: digitoxin, acetyldigitoxin, acetylgitoxin, acetyldigoxin, gitoxin, digoxin.

The plant also contains organic acids: flavonoids (luteolin), saponins. Foxglove leaves are rich in macro- and microelements: magnesium, potassium, calcium, selenium, zinc, iron and ash.

Medicinal properties of foxglove

Foxglove has many medicinal properties. First of all, this plant helps with heart diseases such as acute heart failure.

Foxglove treats and eliminates problems in blood circulation. It is effective for hypertension and edema resulting from heart disease.

When used for treatment, digitalis, unlike many drugs, does not irritate the mucous membranes of the gastrointestinal tract.

Digitalis in medicines can relieve shortness of breath, normalize the pulse and normalize the general condition of the body.

Using this herb you can speed up the healing process of wounds.

Use of digitalis in traditional medicine

In official medicine, digitalis is used for problems with the heart. Pharmacologists obtain digitoxin, gitoxin and cordinide, which are used in the preparation of medicines from the leaves of foxglove purpurea and grandiflora.

To prepare preparations that stimulate the heart muscle, woolly foxglove is used. The leaves of the plant contain celanide and acetyl digitoxin, which are components of such drugs.

Medicines for nervous disorders, hypertension, and healing drugs are prepared on the basis of digitalis or with its participation.

The most famous medicinal preparations from digitalis: Gitalene, digipurene, lantoside, cordigide, digitoxin.

Did you know! From some sources it follows that foxglove was known as a medicine back in the fifth century. However, the first written mention dates back to 1543. The description is in the herbal book of the doctor Leonart Fuchs, who described the plant in detail.

Traditional medicine recipes: treatment of various diseases with digitalis

In folk medicine, medicinal decoctions and infusions of foxglove, as well as powder products, are widely used.

Hypertension

To prepare a remedy for hypertension pour one gram of dry, finely chopped herb with a glass of boiling water (200 ml). Leave the mixture for forty minutes.

Take one dessert spoon three times a day.

Important! Children can take the infusion only from the age of twelve, one teaspoon.

Wound healing

Used for wound healing powder.Grind dry herb leaves to a powder state.

Sprinkle them on the wound. You can cover with a light bandage, preferably gauze, so that the skin can breathe.

Nervous disorders

For problems with the nervous system, prepare tincture of foxglove in alcohol.Pour the dry mixture of foxglove leaves into a dark glass bottle, pour 200 ml of wine alcohol into it. Close the container tightly and leave in a dark place, shaking occasionally.

After a week, strain, pour into a clean container and store in a dark place. A single dose should not exceed thirty drops.

Heart failure

Prepare for heart failure infusion. One gram of crushed leaves is poured with 200 ml of hot water. After infusion, take a teaspoon three times a day. For children, a less concentrated solution is prepared - 0.5 grams per 180 ml of water.

Attention! Do not self-medicate or take the drug for a long time. Some components accumulate in the body and can cause poisoning.

How to prepare medicinal raw materials from foxglove

Foxglove is harvested for medicinal purposes in August – September. It is advisable to prepare foxglove raw materials in dry weather in the evening.

Leaves are cut without petiole: It has no useful elements. In the evening, digitalis contains the highest concentration of nutrients.

On a production scale, leaves are dried in special dryers at temperatures up to 60 degrees. During drying, the raw materials are turned over several times to ensure uniform drying.

The raw material is ready when the top plate turns red. The product should be stored in fabric bags or cardboard containers in a dry place for 24 months.

Contraindications and possible side effects

Glycosides contained in the herb tend to accumulate and are slowly eliminated from the body.

Long-term use of digitalis may result in poisoning. The foxglove plant is a strong plant poison.

Foxglove is an ornamental herbaceous plant that belongs to the Plantain family. This is a perennial herb, but there are also biennial species of this plant. Its stem is rigid and tall (on average its height is 150 cm). The leaves of the plant are lanceolate, alternate, gradually turning into leaves during inflorescence. Foxglove blooms with beautiful flowers of irregular shape. The color of the flowers varies from delicate light yellow to rich purple. The flowers are collected in very decorative dense beautiful inflorescences, racemose.

The flowering period occurs in mid and late summer. The fruit of this herbaceous plant is a capsule with seeds. Foxglove seeds are small, brown in color, and germinate well even after 3 years of proper storage. The plant is very beautiful, but its beauty is deceptive - foxglove is a very poisonous plant.

To date, approximately 35 species of foxglove are known. Most often, this beautiful medicinal plant can be found in the Mediterranean region. Some types of foxglove can be found in Europe, in the western part of Asia and even in the northern part of the African continent. In the territory of modern CIS countries, only 4 species of foxglove grow. This plant prefers deciduous or mixed forests, light meadows and edges.

Harvesting and storage

Dried leaves are most often used for medicinal purposes. Fresh leaves are not used for medicinal purposes. Medicinal material is collected only during the foxglove flowering period. The weather at this time must be dry. The collection is usually carried out in the afternoon, preferably before sunset. It is at this time that foxglove leaves, when exposed to heat and sunlight, contain the greatest amount of useful substances.

The collected medicinal material is dried immediately after collection. Otherwise, the leaves lose their original color. Foxglove leaves are dried in special air or fire dryers, the temperature in which does not exceed +60 degrees. In the dryer, the leaves of this medicinal plant are laid out in a thin layer and constantly turned over during the drying process. Store completely dried medicinal raw materials of foxglove in cardboard boxes in dry, well-ventilated areas. The maximum shelf life is 24 months.

Use in everyday life

Thanks to its high decorative characteristics, foxglove has found its place in gardens, flower beds and borders. This is an indispensable component of landscape design of a personal plot. Foxglove is one of the elements in creating such landscape compositions as alpine hills.

Composition and medicinal properties

Digitalis contains unique microelements, which are the basis of drugs for the complex treatment of almost all heart diseases, for example, severe forms of circulatory disorders, as well as chronic heart failure.
Preparations based on this plant are taken for swelling, as well as for cardiac disorders.
Digitalis has shown itself to be excellent in treating shortness of breath and normalizing pulse.
Medicines that regulate the functioning of the heart muscle are made from digitalis.
Powder from the dried leaves of this plant is used to heal wounds, during attacks of hysteria, and also for disorders of the central nervous system.

Use in folk medicine

For various heart diseases

Approximately 1 g (about 1.4 tsp) of dry crushed foxglove leaves is poured into 1 glass of water (about 200 g). Leave for 12 hours. Take 1 tsp. twice a day for heart disease, regardless of meals. This infusion can be used for the complex treatment of heart diseases in children, but in this case the concentration of the infusion should be less. 1 g of medicinal raw material is poured not 1, but 1.5 tbsp. water.

Wound Healing Powder

The powder is very easy to prepare - you just need to crush the dry leaves of this plant to a powdery consistency. This powder is used for cuts and burns, sprinkling on the sore spot.

Powder for heart diseases

In addition, powder from the leaves of this plant is taken orally for heart diseases. The advantage of this medicine is that it does not have any negative effects on the liver and kidneys. Adult patients should take the powder 0.1 g twice a day. The maximum daily dose of this drug should not exceed 0.5 g for adult patients. The prepared powder should be stored in a transparent glass container made of orange glass, which is tightly sealed. Shelf life - no more than 24 months (subject to airtight storage).

A decoction of foxglove leaves to regulate the functioning of the heart muscle

To prepare a healing decoction, you need to take 20 g of dry medicinal raw materials, pour approximately 600 g of boiling water over it, put it on fire and cook until the amount of liquid in the container is reduced by 1/3. After this, turn off the fire and leave until it cools completely. Then the broth should be strained. Take 1 tbsp. once a day. But the attending physician, depending on the patient’s individual indicators, can increase the dose of the decoction to 2 tbsp.

Alcohol tincture for nervous disorders. Option 1

20 g of dry medicinal raw materials of foxglove should be placed in a dark glass bottle and filled with 200 g of wine alcohol. The bottle must be sealed tightly. Infuse for 7 days in a warm but dark place, shaking its contents from time to time. After this, the tincture must be filtered and stored in a dark glass container. A single dose of this alcohol tincture should not exceed 30 drops.

Alcohol tincture. Option 2

Place 20 g of dry foxglove leaves in a dark glass container and pour in 50 g of pure ethyl alcohol. Leave in a dark place for 7 days, shaking the contents of the container from time to time. After this time has elapsed, the infusion must be strained. A single dose of this alcohol infusion should not exceed 15 drops, which are diluted in a small amount of boiled water immediately before use.

Contraindications

You should not use digitalis-based preparations for long-term treatment of ailments without the advice of a doctor, as this herb tends to accumulate in the body. A large concentration of glycosides in the body, which are eliminated from the body very slowly, can cause symptoms of poisoning of the body.

Foxglove is a very poisonous plant, so do not exceed the dose recommended by a specialist to avoid poisoning.

Symptoms of an overdose of digitalis-based drugs are blue lips, nausea, diarrhea and vomiting.

Taking medications based on this plant is strictly contraindicated for people who suffer from coronary insufficiency, heart disease, myocardial infarction, and infectious diseases.

You should not take digitalis-based medications together with other traditional or traditional medicines that are taken for heart diseases.

Cardiac glycosides are the main group of drugs used to treat acute and chronic heart failure, in which weakening of myocardial contractility leads to cardiac decompensation. The heart begins to consume more energy and oxygen to perform the necessary work (efficiency decreases), ionic balance, protein and lipid metabolism are disturbed, and the heart’s resources are exhausted. Stroke volume decreases with subsequent circulatory disturbances, as a result of which venous pressure increases, venous stagnation develops, hypoxia increases, which contributes to increased heart rate (tachycardia), capillary blood flow slows down, edema occurs, diuresis decreases, cyanosis and shortness of breath appear.
The pharmacodynamic effects of cardiac glycosides are due to their effect on the cardiovascular, nervous systems, kidneys and other organs.
The mechanism of cardiotonic action is associated with the influence of cardiac glycosides on metabolic processes in the myocardium. They interact with the sulfhydryl groups of the transport Na+, K+-ATPase of the cardiomyocyte membrane, reducing the activity of the enzyme. The ion balance in the myocardium changes: the intracellular content of potassium ions decreases and the concentration of sodium ions in the myofibrils increases. This helps to increase the content of free calcium ions in the myocardium by releasing them from the sarcoplasmic reticulum and increasing the exchange of sodium ions with extracellular calcium ions. An increase in the content of free calcium ions in myofibrils promotes the formation of a contractile protein (actomyosin), necessary for cardiac contraction. Cardiac glycosides normalize metabolic processes and energy metabolism in the heart muscle, increase the conjugacy of oxidative phosphorylation. As a result, systole significantly increases.
Increased systole leads to an increase in stroke volume, more blood is ejected from the heart cavity into the aorta, blood pressure increases, presso- and baroreceptors are irritated, the center of the vagus nerve is reflexively excited and the rhythm of cardiac activity slows down. An important property of cardiac glycosides is their ability to lengthen diastole - it becomes longer, which creates conditions for rest and nutrition of the myocardium, and restoration of energy costs.
Cardiac glycosides are able to inhibit the conduction of impulses through the conduction system of the heart, as a result of which the interval between contractions of the atria and ventricles is prolonged. By eliminating reflex tachycardia resulting from insufficient blood circulation (Weinbridge reflex), cardiac glycosides also contribute to prolongation of diastole. In large doses, glycosides increase cardiac automaticity and can cause the formation of heterotopic foci of excitation and arrhythmia. Cardiac glycosides normalize hemodynamic parameters characterizing heart failure, while congestion is eliminated: tachycardia, shortness of breath disappear, cyanosis decreases, and edema is relieved. Diuresis increases.
Some cardiac glycosides have a sedative effect on the central nervous system (glycosides of adonis, lily of the valley). The diuretic effect of cardiac glycosides is mainly due to the improvement of heart function, but their direct stimulating effect on kidney function is also important.