Foxglove is a genus of flowering plants that are used as a medicine for disorders of the heart.
The cardiotropic properties of this flower have long been known. In the first half of the 18th century, it began to be grown in Russia in apothecary gardens, and since 1775, when the works of the British physician Whithering were published, digitalis preparations have firmly taken their place in the practice of treating heart ailments.
Botanical characteristics of foxglove
Genus Digitalis (Digitalis) - perennial flowering plants of the Plantain family with large inflorescences of thimble-like flowers and fragile wrinkled leaves. They bloom in mid-summer (end of June-July), the fruits are ovoid bivalve boxes with small brown seeds. A total of 36 species of digitalis have been described, of which only 5 are used for medical purposes: woolly digitalis (the main source of raw materials), purple, ciliated, large-flowered and rusty.
Initially, the preparation of woolly foxglove was an extract from the leaves of the first and second years. Currently, digitalis glycoside pharmaceutical preparations are obtained from the aerial parts of the plant, mowed before flowering.
All foxgloves are poisonous, which indicates a large amount of biologically active substances and requires careful handling.
Chemical components and uses of foxglove
Foxglove medicines include its main active substances - cardiac glycosides: digitoxin, gitoxin, digoxin, acetyldigoxin and many others, as well as organic acids, saponins, flavonoids.
Most of the active ingredients are of secondary hydrolytic origin, that is, obtained by enzymatic cleavage of natural glycoside molecules.
Foxglove preparations are used in the treatment of many cardiac diseases, mainly related to disorders of the heart and blood vessels:
- Heart failure and various organic lesions of cardiac structures (including as a preventive measure).
- Valvular heart disease leading to decompensation.
- Atrial fibrillation.
- Inflammation and degeneration of the heart muscle.
- Paroxysmal tachycardia in pregnant women.
- Preparing for cardiac surgery.
In case of violations of the conduction system of the heart (blockades) and bradycardia, digitalis glycosides are not prescribed.
How the drug worksfoxglove glycoside
Glycosides isolated from foxglove herb have a specific effect on the heart muscle. In heart failure, the effect of digitalis will be as follows:
- decreased heart rate;
- increased force of myocardial contraction;
- prolongation of the period of relaxation of the heart (diastole).
Digitalis preparations are also successfully used in the treatment of circulatory failure, when the heart cannot cope with the movement of blood through the vessels, which is complicated by edema and trophic disorders. In this case, glycoside drugs are expected to:
- increase in cardiac output (volume of blood leaving the ventricles per contraction);
- more efficient ventricular emptying during systole;
- decrease in the volume of blood circulating in the vessels and, as a result, a decrease in swelling;
- normalization of heart rate with tachycardia;
- acceleration of blood flow in the vascular bed;
- increased vascular tone, which is accompanied by a slight rise in blood pressure.
Foxglove toxicity can provoke unwanted side effects: disorders of the gastrointestinal tract, nervous system, changes in heart rhythm. Unauthorized use of these drugs is unacceptable, the treatment regimen is selected only by a doctor, taking into account the individual characteristics of the patient.
Wooly foxglove medicines
"Celanide" is a fast-acting cardiac glycoside, available in the form of tablets and solution for intravenous injection. Mainindications - circulatory failure, tachycardia, atrial fibrillation.
"Digoxin" is characterized by an increase in myocardial contractility, does not disturb coronary circulation and reduces swelling due to diuretic action. It is administered intravenously and orally. It is prescribed for severe circulatory disorders and during an attack of paroxysmal tachycardia as an emergency.
The therapeutic effect reaches its maximum after a while, when the active substances reach a certain concentration in the body. There is a cumulative effect (accumulative) due to the fact that digitalis preparations are excreted rather slowly.
